A Kaoss pad like device entitled Musical Blackboard was built by Ryan Avery and can be seen in action with this very educational video. The metal sheet interface is used as a sensor for reading body capacitance based on the hand position. The readings are done utilizing a circuit published by the delayed John Simonton of PAIA. Pic microcontroller is then used for processing the values and converting them a stream of serial data that triggers a 40 pin parallel switch circuit. The result is a burst of bends being articulated by the hand movements on the surface of this board. Pure circuit bent/pic microcontroller goodness! More images and the project page is located here. Enjoy.