Rules of the game:
Gagaball is played in any enclosure, the most common being a 12-inch high hexagonal fence made of 1by12 lumber. It can also be played indoors in any room without too many obstacles. The important factor is the ability to bounce the ball off the walls.
a neoprene bouncy ball works great, but some prefer larger dodgeball-size balls
bat the ball with the palm of the hand, with the object of eliminating the other players by hitting them on the knee or below. Hitting the ball over the boundaries without additional contact will eliminate the player that hit the ball - this is called a 'scoop'. Stepping out of the boundaries unless forcefully pushed will also eliminate a player.
Last player remaining is the champion for that round.
To speed up the game when two players remain, the hands-in rule can be invoked, whereby all the spectators kneel around the outer walls and can attempt to eliminate one of the two remaining players.
See the ga-ga wikipedia page for more information concerning other variations.