A few months ago I posted a video here about Sing for Hope's plan to put 60 pianos around New York City for a month. It started last week I think, and already lots of videos are popping up on YouTube. People are even bringing opera to the streets! Click through to YouTube as the blogger format cuts off the video window.
You can see a whole bunch of the Sing for Hope pianos in use here.
I love love love this idea/project/thing. Love it. Love. It.