 Brian Neltner sent in some information about this Sound controlled RGB LED project that he designed. He has a Kickstarter running right now to try to build a 10X10 grid of them for Burning Man. Brian provides the full schematic for those who would like to build their own.
“The goal of the SaikoLED Audio Responsive LED Module is to provide a fully autonomous device capable of collecting audio from the ambient environment and do audio analysis on built in hardware which produces PWM signals capable of controlling ultra high power LED lighting. By putting both audio processing capabilities and a microphone onto the actual LED light, it becomes possible to make arrays of modules of arbitrary shape and size.”