We used this strand of individually addressable LED's from Adafruit last year:
https://www.adafruit.com/products/306
They have arduino code, which is what we used last year, which we interfaced to the cRio (clunkily) through a pair of digital outputs. This year, I took the Arduino library and adapted it to use the SPI.h interface in Wpilib, so we should be able to have the lights respond to a lot more robot, driver, and game actions, and the wiring will be simpler.