MOAR FLASH CHOIRS!
Flash choirs are a variation on flash mobs. I have linked to them before. But I think they have probably hit their peak this season; I have gotten innumerable e-mails about the food court Messiah alone. I am sure we will soon be swamped with every community choir in the nation staging their own flash choir. Here are a few more.
Christmas Food Court Flash Mob sings Hallelujah Chorus in Canada.
Opera Company of Philadelphia "Hallelujah!" Random Act of Culture in Philly.
Opera Company of Philadelphia "Flash Brindisi!" in Philly at the Reading Terminal Market.
Add your own in the comments!