tulpasynth v0.2
"tulpasynth" is a prototype real-time collaborative music creation system that takes advantage of touchscreen gestures for a tangible, responsive UI. It has been generally well-received when I have shown it at CCRMA events and at the 2011 bay area Maker Faire.
tulpasynth screenshot
All of the audio synthesis is done client-side on the iPad and the clients communicate with a Node.js server over websockets to synchronize the data.
More technical details, code, and a demo video can be found on the tulpasynth1 project page.