For a class project, computer-engineering college kids built a system that tracks body movements using a camera and a coloured vest, mapping them to a Space Invaders-type game that requires you to jump to shoot.
You become the controller in the classic game, which is deliberately intended to promote cardiovascular health: There's a sensor that tracks heart rate and sends it to the game component, where it, in theory, could be used "to vary game speed and difficulty." The only sad part about this is that the original game was intended to be Pong, which would've been potentially more of a two-player, and thus more dangerous, thing.
In spite of all this new interaction—and a respectable effort of of building and programming put forth by by the three dudes, Clarkson University juniors Allen, Doug and Matt—the object of the game is still quite simple. As you can hear someone tell the vested Allen in the (unintentionally?) hilarious video on Matt's website, "We fixed it. Now don't die." [The Matt Cave via Hackaday via Ubergizmo]