I'm building a large LED ceiling, with 128 Chinese lanterns illuminated by RGB LEDs, in a 10x20 foot canopy at Maker Faire. It's all controlled with one Arduino. The LED colors are sent to the Arduino from a Processing application. I've tested the update rate beyond 25fps, so the actual LED control and communications are all sorted out.
However, I'm looking for more cool audio-reactive animations to put on the ceiling. I've only come up with a few, and time is growing short. I still have a lot of work to do physically building this. So I'm hoping that some of you Processing users can help me out...download my code, write some fun effects in the 320x160 area and see them simulated, then send your effect functions to me by May 19th (or sooner, otherwise it might not get in). I'll test and integrate everything into the main code, post the final code for everyone to see, and the effects will be admired by tens of thousands of people at Maker Faire. If you're in the area, you should stop by and see your code running on the giant LED array.
Download Processing 1.5: http://processing.org/download/
Download macetrix_sim code: http://www.macetech.com/macetrix_sim.zip
Here's a video of one of my sample effects: