Here's a video of it in action. They're tricky to capture video of (particularly when using a cheap digital camera), but it gives you a rough idea:
This is an incredibly simple project to put together, thanks largely to the LEDs: I use RGB LEDs with color-changing circuitry built right into the package. You just provide power, and the LEDs cycle through red, green, blue, and various combinations thereof. One aspect of these LEDs is that the timing is slightly different in each one, so while they start out in sync, they quickly fall out of phase. I consider this a feature, not a flaw, as it results in the emergence of interesting, seemingly unpredictable patterns.
No soldering is required, just some crimping and a bit of hot glue.
The parts are easy to obtain online, but I also offer kits through Make Magazine's online store, the MakerShed, for $15: