This is an LED wristband for concerts and similar events. Several RF antennas will transmit sync pulses, which will be picked up by the wristband's RF antenna to allow for determination of the wristband's location. This will alllow for some pretty neat effects, such as an LED "wave", or the musician to point their guitar into the crowd an have only that section light up. All sorts of cool things. Additinally, device to device communications will be possible by using the LEDs as a light detector as well. This is designed to be economical, and a lot of fun for concert goers.
Thanks HackaDay for this event. There's a YouTube video going over the basics of this projects in the links section.