Spaceball is a sport that combines volleyball, basketball, jumping a lot and spending $US700 on a fancy trampoline. It's apparently a great workout for potential astronauts, too.
You play the game by trying to throw the ball past your opponent through a netted hole while you both jump around. It certainly looks fun, at least for a little while. I'd probably want to try it out before dropping all that money on it, however.
According to former astronaut Scott Carpenter, it's "the best conditioning exercise for space travel." Sure! Although the weight limit is 90kg per player, so you'd better hope you don't have any really muscular potential astronauts. [Hammacher Schlemmer via Uncrate]