Parkour
 

I'm not crazy enough to actually try it, but I love watching parkour practitioners in action. There's a grace of movement that's difficult to find elsewhere.

Video goodness...

A dramatic scene from a French film called Banlieue 13 featuring heavy use of parkour:


And a long video of David Belle, one of the founders of the practice, and other practitioners demonstrating techniques and discussing the practice (in French):

That second video is awesome, and I hope it gives David Belle more publicity, movie contracts, etc..