The Swiss Institute for Dynamic Systems and Control hosts the Flying Machine Arena. It’s the Swiss cousin of UPenn’s quadrotor assassin. Drone jugglers practice things like “Adaptive High-Performance Maneuvers” and “Flying Inverted Pendulum” in the arena. The drone’s main mission is to kill us in our sleep, but what do they do for fun? Just juggle a ball better than I ever could, here’s a video from the facility’s “Flying Machine Arena””]
Source: https://gizmodo.com/watch-a-murderous-quadrotor-drone-take-a-hacky-sack-bre-5708218