Veteze was inspired at BurningMan to make an LED Vest.

The vest has 465 LEDs (shown in the first picture without the diffusing fur attached) and runs for about 4 hours on battery power.  Even with a low luminosity value, the LEDs are still pretty bright.

You can find the code for the project in this forum thread, as well as some good discussion about how the code was improved with some help of other forum participants.