Have you ever been walking around in your city, and seen somebody in a mask suddenly start dancing? Or perhaps a whole group of people? No, it's not alien mind control - it's actually people being controlled by a vast online conspiracy. They're participating in an alternate reality game called Top Secret Dance Off, where players are issued odd quests like "dance in a crosswalk" or "dance using only your fingers." Usually they vid their exploits and upload them to the site, so you can participate in this secret dance conspiracy while hidden deep in your underground bunker, far from the plague-infested zombies.

And I'm only half-joking about that. Game designer Jane McGonigal invented this game as part of a futurist scenario where she was trying to imagine how people would entertain themselves in a future where peak oil and plagues forced would-be nightclub goers to stay at home. So she dreamed up the Top Secret Dance Off, a nightclub that you can go to via the web. So many people liked the idea that they started playing the game for real, and so now you can have post-apocalyptic fun before the apocalypse.

Yesterday at the Etech Conference in San Jose, McGonigal confessed that of all the games she's helped design, this is her favorite.

Check out Top Secret Dance Off and start dancing!