We use Adafruit Neopixels (
http://www.adafruit.com/products/1461). We use an Arduino Uno to control them, and they are very easy to use (source code can be found on the product page). They run off a 5V power supply, so we are using the old 12V-5V power converter from last year's electronics (and it is legal to use, as long as you follow the Custom Electronics rules R30, R44).