Hallelujah Chorus Flash Mob

Designed to take the audience by surprise, flash mobs are a trendy way to entertain a crowd. A group of people meet in a public place, discreetly interspersed around the room.
They perform a song together, then go about their business as if nothing happened.

Here's a YouTube video of a popular flash mob performance of the Hallelujah Chorus from Handel's Messiah. It takes place in the food court of a mall. Quite the memorable lunch break for these unsuspecting Christmas shoppers!