Over 3,000 people descended on midtown Manhattan in lockstep recently, then collectively took the party to Bryant Park. Along the way they tidied, slow-danced, and high-fived in perfect synchronicity. That's right: it's another Improv Everywhere MP3 Experiment.

You may remember last year's MP3 Experiment in Roosevelt Island, or maybe you've seen Improv Everywhere's No Pants Subway Ride or Ted's Birthday pranks. The group's mission statement is to "cause scenes of chaos and joy in public places," and looking at how much fun this choreographed swarm is having? I'd call it a success. [Improv Everywhere]