My friend Penny in Los Angeles sent me this YouTube link this morning.

Last month, in Valencia, Spain, professional opera singers disguised themselves as shopkeepers in a produce market and then, little by little, surprised all the unknowing shoppers by bursting into song. It's a wonderful way to spend 6 minutes if you have the time to watch:

http://www.youtube.com/watch?v=Ds8ryWd5aFw