N.S.
I would like to suggest Wii Fit for your whole family. It has trainers and all the exercises are fun. You should see a demonstration of it and see if it is something that would work for your son. It really is for the whole family. Yoga, snowboarding, etc. I think it would challenge him. If he plays on this daily this summer he should be in shape by August. It's tough when you advance to higher levels. My son is 11 and he spends alot of time on the balance board included with the game.