Well, it's based off the board game Risk. The gym is separated into 4 or 6 sections. Each area has a medic(somebody on one of those scooter things you sit on)so when you're is hit by a ball, they have to bring you to the wall. The point of the game is to take over all bases, by throwing balls at the other team, and trying to get they're medic out. Normal rules apply as far a throwing and catching, and the medic can be hit in the face, anybody else, the thrower is out. People who are down can also throw balls to get people out, just not catch, I'm pretty sure.