Kaleidostrobe is a visual plug-in for iTunes on Mac OS X. It generates multi-layered animated kaleidoscopic patterns that are beat synched to music. It works best with music that has a prominent beat with lots of bass, but it is fun to watch with all types of music.
PowerPC G3 333MHz or better
(iMac 333 or later model Mac recommended), Mac OS 10.1.4 or later, iTunes 2.0 or later, Hardware Accelerated OpenGL Graphics Card (ATI Rage Pro or better)