DaVinci is an App for Microsoft Surface Table. The creators have ported this to Kinect.
Gestures are used to create objects and control the physics of the environment. Your hands appear in the interface which allows you to literally grab objects out of thin air and move them in the environment. Additional gestures allow you to affect the gravity, magnetism and attraction.
Right now i thing this is the best Kinect usage i have ever seen. Watch the video to understand .