The Spinner Synth is a prototype MIDI controller made with a piece of scrap wood, a webcam and some tape.
This is a circular controller for a synthesizer, using the openCV visualization library to analyze a series of points on a rotating wheel, and generate MIDI events.
Details here.
via Mahto:
You should try that with a map of the globe (the polar-centric one) to see what the Earth would sound like as a musical instrument.