Pilight is a lighting control software designed to be run on Raspberry Pi Mini-Computers. It comes with a number of supported output plugins and allows you to build your own effects in Python. It comes with an audio analysis engine and an early stage beat detection.
Pilight is designed to run headless and comes with different input and control mechanisms, e.g. browser control or IR remote control via LIRC.
The source code of pilight is available on github: https://github.com/jketterl/pilight