A flash mob is basically performance art, but on a grand scale. Large groups of people quickly assemble, perform a particular action and then disperse. Large population centers like New York and Stockholm are great spots for flash mobs since so many people are out and about. Those who participate receive a call or text message on their cell phones to show up somewhere and then they are told what they’ll be performing. The first flash mob was a giant pillow fight, but they’ve also invaded an Apple Store as zombies and danced silently in London’s Victoria Station.

Of all the flash mob events I’ve seen, this one in New York’s Grand Central Station has to be the best. Over 200 people walk in, and freeze solid for about five minutes. Check it out:

I love the expressions of the observers as they walk around stunned by this odd sight. The participants did a great job of finding poses that make them seem totally caught in time. The one woman eating a banana, the guy who dropped the papers. Somehow none of them crack a smile or break character while frozen and the crowd is fascinated.

My favorite line is the one onlooker who says near the end “I thought it was only me.” Like a scene out of Clockstoppers, hundreds of people managed to bend the perceptions of strangers for a brief moment. Reality is called into question and art is born. Pure Internet gold.