Stringer is a virtual string instrument played with a Kinect 3d camera. A person can draw his/her own instrument in the air using gestures. Multiple people can play at once, through separate hand-tracking. Strings can be set to morph as people interact, with length determining pitch, creating a constantly changing melody.
More info: Alex's blog post.
Instructions coming soon.
You can also clone the project with Git by running:
$ git clone git://github.com/afeld/stringer