I had this idea inspired by the game Robot Unicorn Attack. Here is a high concept of the design:
2D Sidescroller Obstacle Course
Platform: XBox Kinect
The basic idea is that there is a character on the screen who is always running, and along the way there will be obstacles in front of her. The player must overcome the obstacles by jumping, leaning, squatting, and other "active" motions.
Posts with more details will follow if I pursue this idea further.