I like finding a steep hill/mountain with trees and running down as fast as I can. After hiking up, of course. Aspen forests are fun because you can swing from tree to tree (sometimes without feet touching the ground). It's kinda hard on the knees though. With the right boots you can "edge" the dirt, kinda' like skiing I guess.
Okay, so I'd really like a nice mountain bike but don't have the money.
Otherwise it's skateboarding, street or pool, and this year a good bit of weightlifting. I want to try more olympic-style lifts, as I've done a little bit of that and it feels great and is probably really good for snowboarding.