Light up pillars of audio goodness
Kevin Roach build a light grid system that uses FMod and Visual Basic 6 for his software to power the MIT disco boards. His software isn't open for source viewing but you can view his videos over at his site along with download it.
For those who't aren't aware about FMod, FMod is a cross platform audio library with a object oriented API. If you're planning to do some stuff with audio, you may want to check it out over at www.fmod.org.