Football

Association football, more commonly known as football or soccer, is a team sport played between two teams of eleven players using a spherical ball. Association football is the most popular football variant worldwide, and is widely considered to be the most popular sport in the world.
The game is played on a rectangular grass or artificial turf field, with a goal in the centre of each of the short ends. The object of the game is to score by driving the ball into the opposing goal. In general play, the goalkeepers are the only players allowed to use their hands or arms to propel the ball; the rest of the team usually use their feet to kick the ball into position, occasionally using their torso or head to intercept a ball in midair. The team that scores the most goals by the end of the match wins. If the score is tied at the end of the game, either a draw is declared or the game goes into extra time and/or a penalty shootout, depending on the format of the competition.
The modern game was codified in England following the formation of The Football Association, whose 1863 Laws of the Game created the foundations for the way the sport is played today. Football is governed internationally by the Fédération Internationale de Football Association (International Federation of Association Football), commonly known by the acronym FIFA. The most prestigious international football competition is the FIFA World Cup, held every four years. This event, the most widely viewed in the world, boasts an audience twice that of the Summer Olympic Games.

Players, equipment and officials:

Each team consists of a maximum of eleven players (excluding substitutes), one of whom must be the goalkeeper. Competition rules may state a minimum number of players required to constitute a team; this is usually seven. Goalkeepers are the only players allowed to play the ball with their hands or arms, provided they do so within the penalty area in front of their own goal. Though there are a variety of positions in which the outfield (non-goalkeeper) players are strategically placed by a coach, these positions are not defined or required by the Laws.
The basic equipment or kit players are required to wear includes a shirt, shorts, socks, footwear and adequate shin guards. Headgear is not a required piece of basic equipment, but players today may choose to wear it to protect themselves from head injury. Players are forbidden to wear or use anything that is dangerous to themselves or another player, such as jewellery or watches. The goalkeeper must wear clothing that is easily distinguishable from that worn by the other players and the match officials.
A number of players may be replaced by substitutes during the course of the game. The maximum number of substitutions permitted in most competitive international and domestic league games is three, though the permitted number may vary in other competitions or in friendly matches. Common reasons for a substitution include injury, tiredness, ineffectiveness, a tactical switch, or timewasting at the end of a finely poised game. In standard adult matches, a player who has been substituted may not take further part in a match.
A game is officiated by a referee, who has "full authority to enforce the Laws of the Game in connection with the match to which he has been appointed" (Law 5), and whose decisions are final. The referee is assisted by two assistant referees. In many high-level games there is also a fourth official who assists the referee and may replace another official should the need arise.

Baseball

Baseball is a bat-and-ball sport played between two teams of nine players each. The goal is to score runs by hitting a thrown ball with a bat and touching a series of four bases arranged at the corners of a ninety-foot square, or diamond. Players on one team (the batting team) take turns hitting against the pitcher of the other team (the fielding team), which tries to stop them from scoring runs by getting hitters out in any of several ways. A player on the batting team can stop at any of the bases and later advance via a teammate's hit or other means. The teams switch between batting and fielding whenever the fielding team records three outs. One turn at bat for each team constitutes an inning; nine innings make up a professional game. The team with the most runs at the end of the game wins.
Evolving from older bat-and-ball games, an early form of baseball was being played in England by the mid-eighteenth century. This game and the related rounders were brought by British and Irish immigrants to North America, where the modern version of baseball developed. By the late nineteenth century, baseball was widely recognized as the national sport of the United States. Baseball on the professional, amateur, and youth levels is now popular in North America, parts of Central and South America and the Caribbean, and parts of East Asia. The game is sometimes referred to as hardball, in contrast to the derivative game of softball.
In North America, professional Major League Baseball (MLB) teams are divided into the National League (NL) and American League (AL). Each league has three divisions: East, West, and Central. Every year, the champion of Major League Baseball is determined by playoffs that culminate in the World Series. Four teams make the playoffs from each league: the three regular season division winners, plus one wild card team. Baseball is the leading team sport in both Japan and Cuba, and the top level of play is similarly split between two leagues: Japan's Central League and Pacific League; Cuba's West League and East League. In the National and Central leagues, the pitcher is required to bat, per the traditional rules. In the American, Pacific, and both Cuban leagues, there is a tenth player, a designated hitter, who bats for the pitcher. Each top-level team has a farm system of one or more minor league teams. These teams allow younger players to develop as they gain on-field experience against opponents with similar levels of skill.

Rules and gameplay:

A game is played between two teams, each composed of nine players, that take turns playing offense (batting or hitting) and defense (fielding or pitching). A pair of turns, one at bat and one in the field, by each team constitutes an inning; there are nine innings in a game. One team—customarily the visiting team—bats in the top, or first half, of every inning; the other team—customarily the home team—bats in the bottom, or second half, of every inning. The goal of a game is to score more points (runs) than the other team. The players on the team at bat attempt to score runs by circling, or completing a tour of, the four bases set at the corners of the square-shaped baseball diamond. A player bats at home plate and must proceed counterclockwise to first base, second base, third base, and back home in order to score a run. The team in the field attempts both to prevent runs from scoring and to record outs, which remove opposing players from offensive action until their turn in their team's batting order comes up again. When three outs are recorded, the teams switch roles for the next half-inning. If the score of the game is tied after nine innings, extra innings are played to resolve the contest. Children's games are often scheduled for fewer than nine innings.[79]

The game is played on a field whose primary boundaries, the foul lines, extend forward from home plate at 45-degree angles. The 90-degree area within the foul lines is referred to as fair territory; the 270-degree area outside them is foul territory. The part of the field enclosed by the bases and several yards beyond them is the infield; the area farther beyond the infield is the outfield. In the middle of the infield is a raised pitcher's mound, with a rectangular rubber plate (the rubber) at its center. The outer boundary of the outfield is typically demarcated by a raised fence, which may be of any material and height (many amateur games are played on fields without a fence). Fair territory between home plate and the outfield boundary is baseball's field of play, though significant events can take place in foul territory, as well.[80]
There are three basic tools of baseball: the ball, the bat, and the glove or mitt:
The baseball is about the size of an adult's fist, around 9 inches (23 centimeters) in circumference. It has a rubber or cork center, wound in yarn and covered in white cowhide, with red stitching.[81]
The bat is a hitting tool, traditionally made of a single, solid piece of wood; other materials are now commonly used for nonprofessional games. It is a hard round stick, about 2.5 inches (6.4 centimeters) in diameter at the hitting end, tapering to a narrower handle and culminating in a knob. Bats used by adults are typically around 34 inches (86 centimeters) long, and not longer than 42 inches (106 centimeters).[82]
The glove or mitt is a fielding tool, made of padded leather with webbing between the fingers. As an aid in catching and holding onto the ball, it takes various shapes to meet the specific needs of different fielding positions.[83]
Protective helmets are also standard equipment for all batters.[84]
At the beginning of each half-inning, the nine players on the fielding team arrange themselves around the field. One of them, the pitcher, stands on the pitcher's mound; the pitcher begins the pitching delivery with one foot on the rubber, pushing off it to gain velocity when throwing toward home plate. Another player, the catcher, squats on the far side of home plate, facing the pitcher. The rest of the team faces home plate, typically arranged as four infielders—who set up along or within a few yards outside the imaginary lines between first, second, and third base—and three outfielders. In the standard arrangement, there is a first baseman positioned several steps to the left of first base, a second baseman to the right of second base, a shortstop to the left of second base, and a third baseman to the right of third base. The basic outfield positions are left fielder, center fielder, and right fielder. A neutral umpire sets up behind the catcher.[85

Gameplay starts with a batter standing at home plate, holding a bat. The batter waits for the pitcher to throw a pitch (the ball) toward home plate, and attempts to hit the ball with the bat. The catcher catches pitches that the batter does not hit—as a result of either electing not to swing or failing to connect—and returns them to the pitcher. A batter who hits the ball into the field of play must drop the bat and begin running toward first base, at which point the player is referred to as a runner (or, until the play is over, a batter-runner). A batter-runner who reaches first base without being put out (see below) is said to be safe and is now on base. A batter-runner may choose to remain at first base or attempt to advance to second base or even beyond—however far the player believes can be reached safely. A player who reaches base despite proper play by the fielders has recorded a hit. A player who reaches first base safely on a hit is credited with a single. If a player makes it to second base safely as a direct result of a hit, it is a double; third base, a triple. If the ball is hit in the air within the foul lines over the entire outfield (and outfield fence, if there is one), it is a home run: the batter and any runners on base may all freely circle the bases, each scoring a run. This is the most desirable result for the batter. A player who reaches base due to a fielding mistake is not credited with a hit—instead, the responsible fielder is charged with an error.[86]
Any runners already on base may attempt to advance on batted balls that land, or contact the ground, in fair territory, before or after the ball lands; a runner on first base must attempt to advance if a ball lands in play. If a ball hit into play rolls foul before passing through the infield, it becomes dead and any runners must return to the base they were at when the play began. If the ball is hit in the air and caught before it lands, the batter has flied out and any runners on base may attempt to advance only if they tag up or touch the base they were at when the play began, as or after the ball is caught. Runners may also attempt to advance to the next base while the pitcher is in the process of delivering the ball to home plate—a successful effort is a stolen base.[87]
A pitch that is not hit into the field of play is called either a strike or a ball. A batter against whom three strikes are recorded strikes out. A batter against whom four balls are recorded is awarded a base on balls or walk, a free advance to first base. (A batter may also freely advance to first base if any part of the batter's body or uniform is struck by a pitch before the batter either swings at it or it contacts the ground.) Crucial to determining balls and strikes is the umpire's judgment as to whether a pitch has passed through the strike zone, a conceptual area above home plate extending from the midpoint between the batter's shoulders and belt down to the hollow of the knee.[88]
A strike is called when one of the following happens:
The batter lets a well-pitched ball (one within the strike zone) go through to the catcher.
The batter swings at any ball (even one outside the strike zone) and misses.
The batter hits a foul ball—one that either initially lands in foul territory or initially lands within the diamond but moves into foul territory before passing first or third base. If there are already two strikes on the batter, a foul ball is not counted as a third strike; thus, a foul ball cannot result in the immediate strikeout of the batter. (There is an exception to this exception: a two-strike foul bunt is recorded as a third strike.)
A ball is called when the pitcher throws a pitch that is outside the strike zone, provided the batter has not swung at it.[88][89]

While the team at bat is trying to score runs, the team in the field is attempting to record outs. Among the various ways a member of the batting team may be put out, five are most common:
The strikeout: as described above, recorded against a batter who makes three strikes before putting the ball into play or being awarded a free advance to first base.
The flyout: as described above, recorded against a batter who hits a ball in the air that is caught by a fielder, whether in fair territory or foul territory, before it lands, whether or not the batter has run.
The ground out: recorded against a batter (in this case, batter-runner) who hits a ball that lands in fair territory which, before the batter-runner can reach first base, is retrieved by a fielder who touches first base while holding the ball or relays it to another fielder who touches first base while holding the ball.
The force out: recorded against a runner who is required to attempt to advance—either because the runner is on first base and a batted ball lands in fair territory, or because the runner immediately behind on the basepath is thus required to attempt to advance—but fails to reach the next base before a fielder touches the base while holding the ball. The ground out is technically a special case of the force out.
The tag out: recorded against a runner who is touched by a fielder with the ball or a glove holding the ball, while the runner is not touching a base.
It is possible to record two outs in the course of the same play—a double play; even three—a triple play—is possible, though this is very rare. Players put out or retired must leave the field, returning to their team's dugout or bench. A runner may be stranded on base when a third out is recorded against another player on the team. Stranded runners do not benefit the team in its next turn at bat—every half-inning begins with the bases empty of runners.[90]
An individual player's turn batting or plate appearance is complete when the player reaches base (or hits a home run), makes an out, or hits a ball that results in the team's third out, even if it is recorded against a teammate. On rare occasions, a batter may be at the plate when, without the batter's hitting the ball, a third out is recorded against a teammate—for instance, a runner getting caught stealing (tagged out attempting to steal a base). A batter with this sort of incomplete plate appearance starts off the team's next turn batting; any balls or strikes recorded against the batter the previous inning are erased. A runner may circle the bases only once per plate appearance and thus can score at most a single run per batting turn. Once a player has completed a plate appearance, that player may not bat again until the eight other members of his team have all taken their turn at bat. The batting order is set before the game begins, and may not be altered except for substitutions. Once a player has been removed for a substitute, that player may not reenter the game. Children's games often have more liberal substitution rules.[91]
If the designated hitter (DH) rule is in effect, each team has a tenth player whose sole responsibility is to bat (and run). The DH takes the place of another player—almost invariably the pitcher—in the batting order, but does not field. Thus, even with the DH, each team still has a batting order of nine players and a fielding arrangement of nine players.[92]

Basketball

Basketball is a team sport in which two teams of five active players each try to score points against one another by placing a ball through a 10 foot (3.048 m) high hoop (the goal) under organized rules. Basketball is one of the most popular and widely viewed sports in the world.[1]
Points are scored by throwing (shooting) the ball through the basket from above; the team with more points at the end of the game wins. The ball can be advanced on the court by bouncing it (dribbling) or passing it between teammates. Disruptive physical contact (foul) is penalized and there are restrictions on how the ball can be handled (violations).
Through time, basketball has developed to involve common techniques of shooting, passing and dribbling, as well as players' positions, and offensive and defensive structures. Typically, the tallest members of a team will play center or one of two forward positions, while shorter players or those who possess the best ball handling skills and speed, play the guard positions. While competitive basketball is carefully regulated, numerous variations of basketball have developed for casual play. In some countries, basketball is also a popular spectator sport.
While competitive basketball is primarily an indoor sport, played on a basketball court, less regulated variations played in the outdoors have become increasingly popular among both inner city and rural group.

Equipment:

The only essential equipment in a basketball game is the basketball and the court: a flat, rectangular surface with baskets at opposite ends (or in the case of 3-on-3 street basketball, half a court with one basket). Competitive levels require the use of more equipment such as clocks, scoresheets, scoreboard(s), alternating possession arrows, and whistle-operated stop-clock systems.

A regulation basketball court in international games is 28 by 15 meters (approx. 92 by 49 ft) and in the NBA is 94 by 50 feet (29 by 15 m). Most courts are made of wood, usually maple.[22] A steel basket with net and backboard hang over each end of the court. At almost all levels of competition, the top of the rim is exactly 10 feet (3.05 m) above the court and 4 feet (1.2 m) inside the baseline. While variation is possible in the dimensions of the court and backboard, it is considered important for the basket to be of the correct height; a rim that is off by but a few inches can have an adverse effect on shooting.
There are also regulations on the size a basketball should be. If women are playing, the official basketball size is 28.5" in circumference (size 6) and a weight of 20 oz. For men, the official ball is 29.5" in circumference (size 7) and weighs 22 oz.

Positions and structures:

Although the rules do not specify any positions whatsoever, they have evolved as part of basketball. During the first five decades of basketball's evolution, one guard, two forwards, and two centers or two guards, two forwards, and one center were used. Since the 1980s, more specific positions have evolved, namely:
point guard: usually the fastest player on the team, organizes the team's offense by controlling the ball and making sure that it gets to the right player at the right time
shooting guard: creates a high volume of shots on offense; guards the opponent's best perimeter player on defense
small forward: often primarily responsible for scoring points via cuts to the basket and dribble penetration; on defense seeks rebounds and steals, but sometimes plays more actively
power forward: plays offensively often with his back to the basket; on defense, plays under the basket (in a zone defense) or against the opposing power forward (in man-to-man defense)
center: uses height and size to score (on offense), to protect the basket closely (on defense), or to rebound.
The above descriptions are flexible. On some occasions, teams will choose to use a three guard offense, replacing one of the forwards or the center with a third guard. The most commonly interchanged positions are point guard and shooting guard, especially if both players have good leadership and ball handling skills.
There are two main defensive strategies: zone defense and man-to-man defense. Zone defense involves players in defensive positions guarding whichever opponent is in their zone. In man-to-man defense, each defensive player guards a specific opponent and tries to prevent him from taking action.
Offensive plays are more varied, normally involving planned passes and movement by players without the ball. A quick movement by an offensive player without the ball to gain an advantageous position is a cut. A legal attempt by an offensive player to stop an opponent from guarding a teammate, by standing in the defender's way such that the teammate cuts next to him, is a screen or pick. The two plays are combined in the pick and roll, in which a player sets a pick and then "rolls" away from the pick towards the basket. Screens and cuts are very important in offensive plays; these allow the quick passes and teamwork which can lead to a successful basket. Teams almost always have several offensive plays planned to ensure their movement is not predictable. On court, the point guard is usually responsible for indicating which play will occur.
Defensive and offensive structures, and positions, are more emphasized in higher levels in basketball; it is these that a coach normally requests a time-out to discuss.

Playing regulations:

Games are played in four quarters of 10 (international) or 12 minutes (NBA). College games use two 20-minute halves while most high school games use eight minute quarters. Fifteen minutes are allowed for a half-time break, and two minutes are allowed at the other breaks. Overtime periods are five minutes long. Teams exchange baskets for the second half. The time allowed is actual playing time; the clock is stopped while the play is not active. Therefore, games generally take much longer to complete than the allotted game time, typically about two hours.
Five players from each team (out of a twelve player roster) may be on the court at one time. Substitutions are unlimited but can only be done when play is stopped. Teams also have a coach, who oversees the development and strategies of the team, and other team personnel such as assistant coaches, managers, statisticians, doctors and trainers.
For both men's and women's teams, a standard uniform consists of a pair of shorts and a jersey with a clearly visible number, unique within the team, printed on both the front and back. Players wear high-top sneakers that provide extra ankle support. Typically, team names, players' names and, outside of North America, sponsors are printed on the uniforms.
A limited number of time-outs, clock stoppages requested by a coach for a short meeting with the players, are allowed. They generally last no longer than one minute unless, for televised games, a commercial break is needed.
The game is controlled by the officials consisting of the referee ("crew chief" in men's college and the NBA), one or two umpires ("referees" in men's college and the NBA) and the table officials. For college, the NBA, and many high schools, there are a total of three referees on the court. The table officials are responsible for keeping track of each teams scoring, timekeeping, individual and team fouls, player substitutions, team possession arrow, and the shot clock.