SIOnCampus just posted a good article on how to accomplish that and more:

With school in session, we're all packed in the dorms. We can easily get our posse together for a quick pick-up game of basketball, and we can pester a roommate to spot us at the gym. But when school's out, and everyone splits up to go home for the summer, this becomes a bit more difficult. But don't fret. The Internet offers several solutions. And none of them are on MySpace. [SIOnCampus]

Get off the couch: Five ways to get your sport on this summer