Swarm of 49 Hummingbird Quadrocopters

Ars Electronica Futurelab and Ascending Technologies, featured a world record forty-nine AscTec Hummingbird quadrocopters in a synchronized and choreographed, LED-lit dance. The 500 gram robots were carrying lights and had special radio receivers and slightly modified firmware, but otherwise, they apparently just relied on GPS for positional control.

via ieee spectrum