I created an installation for Yuri's Night 2008 at Moffett Field, called Finger Painting with Planets. The picture here shows what it looked like, and here's a closeup of the custom controller I built. People used the multitouch pads to place and move planet-like objects whose simulated gravitational attraction created the graphics, which you can see demonstrated in the video to the right. Here's instructions for using it. The software used Salvation as a freeframe host, a freeframe plugin using Python to do the graphics with Cairo libraries, and Chipmunk to help do the physics simulation. The freeframe plugin communicated using OSC to and from KeyKit, which managed all the device interaction and music generation. Music was generated both directly by the pads and as a result of planet collisions. The controllers used a Doepfer USB64 to interface with the knobs and buttons, and a Pertelian LCD display to label the knobs and display their values.