Paddle ball (sport)
Paddle-ball is a sport that is played on a court half the size of a tennis court, using paddle racquets amongst two players (single game) or in doubles (4 players). The paddle is made of wood or graphite, and has holes to reduce air friction. Necessary equipment
To play paddle ball, it's necessary to have a paddle (resembling a racquetball paddle) that is no longer than 18 inches and no wider than 9 1/2 inches. The paddle-ball is made of plastic paddleball, the size of a softball. Air holes in the ball give to it less friction. Paddleballs come in yellow and light green. Court
Paddle-ball is normally played on a court that is 20 feet wide and 50 feet long, with a wall that is 16 feet in height. The court has a short line, a set of service markers, two side lines and a long line. The service zone is the area between the short line and the service markers. At the start of the play, one person must stand inside the service zone and strike the ball against the wall. The server must stay within the service zone until the ball crosses the short line. Gameplay and scoring rules
During the serve, the ball must cross the short line, and the server must remain in the service box. If the ball bounces before crossing this line, a "short" is called; if it bounces beyond the long line, it is a "long out". If the server steps out of the service zone during the serve, it's termed as a "fault". A server has two chances to execute a valid serve, failing which the receiver wins the point and the players swap roles. Scoring follows a progression of 15, 30, and 40 points before a player wins the game. Once a valid serve is executed, the receiver must return the ball before it bounces twice on the court. The play continues with players alternately hitting the ball, avoiding a double bounce or hitting it out of bounds to prevent losing the point. If a ball, deemed to have been on track to hit the wall, strikes the server upon return, the point is restarted. Players switch roles if the receiver wins a point. Interferences such as intentional blocks or safety concerns can prompt a game restart. Deliberate interference by the server results in a point loss. Technicalities

Serving
 Stepping on or over short line, sideline or service marker is a fault. Ball is short on serve if the ball does not carry across the short line before bouncing. This is a fault. Ball is long on serve if ball carries past the long line without on court bounce or being received. This is a fault. Serving between the legs is an automatic fault. Server is allowed (1) fault per service point. A second fault means server forfeits serve. This resets every new service point attempt. If any serve is wide, the server forfeits the serve. If server swings and fails to hit the ball, the server forfeits the serve. If served ball hits the ground before hitting the wall, server forfeits the serve. Server's partner must remain outside the sideline in between the service line and the short line until the served ball crosses the short line. Receiving serve
 Receiver must hit the ball before it bounces twice. Receiver must wait until ball crosses service line before returning serve. Receiver may hit ball before it bounces. If the server crosses their body with a serve, or if the served ball bounces within one foot of the server, a block may be called by receiver, and point is replayed. Game play
 If struck ball hits the striker or partner, they forfeit the point. Until the ball is struck or bounces twice, player(s) can swing any number of times. After hit, ball must hit the wall before it hits the floor. Off wall, ball may be returned without bouncing. Opponent(s) MAY NOT hinder striker by moving during the strikers swing if they are between striker and wall. If they do, opponents forfeit point to striking team. They may move if they are behind striker, and not impairing the striker's ability to return the ball. If striking player lets the ball touch any part of their body, it's out against them. If struck ball will hit wall before bouncing, but hits opponent first, play is stopped and point is replayed. If struck ball doesn't hit wall before bouncing but hits the opponent, the striker forfeits point. If striker's paddle contacts the opponent on forward motion, striker forfeits point. If striker's paddle contacts the opponent on back-swing, point is replayed. The ball is in play until it bounces twice. If paddle is dropped during play, that player forfeits point. Player can call "safety" out of fear for injuring opponent with ball or paddle. To call "safety", you must be able to return ball, and immediately call out "block" or "safety". Any needless "safety" call is a penalty. If the ball breaks, the game is paused and the point is replayed. Ball's played over if it hits either a foreign object or if a foreign object enters court. A referee is not necessary in this particular game. It can be played with mutual or compromised agreements amongst the players. Additional rules for single play
Server can serve anywhere within service box and must serve to major area of the court. A major area is where the server begins serve. If the ball lands anywhere outside the major area, it's out. Serving from middle, server must declare with side of court being served into. Serving into a minor area must be declared or it's a fault. References

External links
 The United States Paddleball Association, 2006
 National Paddleball Association (NPA)

Racket sports
Forms of tennis
Sports rules and regulations by sport