The F1 topic got me thinking about sports that aren't really sports, and I think there would be a huge market for EXTREME versions of certain non-sports.
For example- I know there's a version of golf where you have to sprint to your shot each time because both # of strokes and overall time is taken into consideration. That is awesome. I would definitely watch that, especially if there were two people playing/racing the same hole together.
Applied to bowling- I suggest making the bowlers race down the lanes to clean up the pins they missed each throw, then race back to throw again.
Poker- No great ideas... Just don't call it a sport.
What other non-sports can be improved with some physical activity?