I go powerkiting in the summer.  It is a superb upper-body workout.  I have gottem pretty good at handling my 5 meter (15 ft wide) kite, so I am looking for a mountainboard to ride with it.  Other than that I like biking and inline skating.
Other "sideways" sports are always good for off-season coodination - skateboarding, mountainboarding, golf, etc...

i ride 20 inch bikes, skateboard, swim, play tennis, not this summer though, im going to build sand castles, im in the army.

I know this is an old thread, but I thought a lot of these pastimes were interesting. I usually sit on my butt and play whatever new game is out on PS3 ( grand theft auto 4 currently ). But to be a bit more on the target of the topic, I've recently purchased a freeboard and besides being scared of it due to lack of proper safety equipment, I've tried it out and if anyone is looking for a close to snowboarding feel I would suggest it. Check out this site for more info if you're interested.

www.freebord.com    ( yes that's the way they spell it  )

It's basically an overgrown skateboard with an extra wheel in the center of each truck. I'm figuring you guys already know about them, but I didn't see it in anyone's list so it's worth checking out if you haven't. have a great summer everybody!

Has anyone gone anywhere or done anything interesting so far this summer? All its done here in Vermont is rain rain rain