IEEE Spectrum writes:
In October of 2009, we wrote about the very first version of EPFL's AirBurr micro air vehicle, called HoverMouse. It was an innovative design: a roll cage protected the MAV's engine and flight surfaces, enabling it to crash into walls and floors without damage and then take off again, provided it had enough room to get airborne. Seven iterations later, the AirBurr V8 Samurai includes an active self-righting mechanism that allows it to crash and take off again even in rugged and cluttered environments.
AirBurr's latest trick involves first crashing into something and falling to the ground, which I imagine was a pretty easy thing to get it to do. Second, the MAV rolls over onto its side thanks to a clever arrangement of carbon fiber caging plus a carefully designed center of gravity. Third, AirBurr activates an "Active Recovery System" consisting of carbon fiber legs that deploy out from the body, pushing the body of the MAV into a vertical position from which it can lift off straight up. Watch:
Read the whole IEEE Spectrum piece for lots of pictures of previous versions and background on the research.