Here's another disc sport (in response to kanjam). There is actually a rec league in conjunction to the Ultimate rec leagues in Atlanta. The game is fun, takes a little time to get used to the differences between Ulti and Goalty, (different types of cutting, different throws), and the subbing on the fly is different.
http://www.goaltimate.com/goaltimate.htmThe game is fast paced (non-stop action) and will definitely give you a work out. It is also good for pick up since it only takes 8 people to play (so if you are short a few for ultimate, just hope someone has a goalty kit in their car).