It's tough to motivate yourself to get a good amount of exercise. It is equally tough to stop playing video games, as they are so very fun. What if you could solve both problems at once?
Well, Project Excite Bike doesn't stop you from playing video games, but it does make playing video games more productive. It does this by hooking a stationary bike up to an Xbox 360, with pedaling controlling one button. This works great for racing games where you need to basically hold the gas down the entire time you play. It's a custom job, but if you're really motivated I'm sure you could configure this for yourself.