From Emanuele Feronato: "TwinSpin was a fun Flash game I am not even able to find anymore. If you know a working link, please tell me. All I was able to find at the moment is an iOS version.
Basically you have two spinning orbs. Each orb spins around the other orb, one clockwise and one counter-clockwise. Tapping or clicking the screen, the spinning orb stops and the other orb starts spinning."