Are you a geek with a punky side? Adafruit has put together a Punk LED Collar kit that might be for you. It takes a cue from the classic spiked collar, but replaces the spikes with LEDs. Ten bulbs adorn the collar, and a built-in potentiometer controls the brightness.
The kit uses common electronics parts, and they provide a tutorial for the build if you have the parts on hand yourself.