Amazing Autonomous Quadrocopter Acrobatics
"This video shows two quadrocopters capable of not only balancing an inverted pendulum, but also of launching it off the vehicle and catching it again." Keep in mind that these autonomous quadrocopters (and the ones you may have seen flying in unison) only work in special motion-tracking rooms with cameras mounted on all corners. The cameras sense the relative positions of the pole and quadrocopters via color makers (pink, here) and ping-pong ball sized spheres, much like in motion-capture animation. Only about half a dozen of these rooms exist in the world right now, so don't expect to see these at local Maker Faires for another few years.