The game takes place in a garage. There are 2 players. It is very much like racquetball, except the racquet is your hand.
The garage is divided according to the players mutual agreement on what the goal/score lines are.
You must open-hand slap the ball, which is a dodgeball, onto the floor once before the other player can return.
You score by getting the ball past the other player's zone.
You can bounce the ball off the walls, furniture, lamps, etc., but it can only bounce off the floor once.
Drinking is usually involved, and you can expect to break some things; but things you probably don't give a shit about anyway. This sounds strange, but it gets hysterical.
Joe: Wanna play dodgeball?
Blow: What? It's midnight, there's only two of us and we're half drunk in Mom's garage.
Joe: Wanna play garageball?