I just finished my first musical instrument based on the Kinect controller. The Therenect is a virtual Theremin, which defines two virtual antenna points that allow controlling the pitch and volume of a simple oscillator. The distance to these points can be controlled by freely moving the hand in three dimensions or by reshaping the hand, which allows gestures that are quite similar to playing an actual Theremin.
At the moment I am getting in contact with some trained Theremin players in order to tune the application to fully simulate the behavior of an actual Theremin. We will then publish some additional videos with a more musical experience … The software has been developed using the Open Frameworks and OpenKinect libraries and will be released under an open source license when it is more mature.