Kickball is a game played by both youth and adults. Similar to baseball this game has four plates, one ball but no bat which makes the game more easily accessible for youth to have an introduction to other sports without specialized equipment or a certain skill set.
According to the World Adult Kickball Association Rulebook.
2.04 The official kickball is the red WAKA Logo Kickball with a pressure of 1.5 pounds per square inch. No other ball is approved for use in WAKA kickball games. Do not over or under inflate the ball.
World Adult Kickball Association Rulebook – http://www.kickball.com/files/KICKBALL_OFFICIAL_RULES_2009.pdf
Photo – http://www.theforecaster.net/node/28991/