This story took place almost four years ago, but I just heard about it today. Here's the synopsis:
On January 12, 2007, in a subway station in Washington, D.C., a musician took out his violin and began playing. It was almost 8:00 am, and during the next 43 minutes he played six classical pieces. 1097 people passed by during that time, most hurrying to get to work on time. Of those, only seven people stopped what they were doing and just listened. Twenty-seven people dropped money into his violin case, the grand total being $32.17 ($20 of that was given by one woman who recognized who the musician was). Three days before, this musician had played in Boston, where the cheapest seats were $100.
The musician was Joshua Bell, and this was a social experiment organized by The Washington Post. You can read the article here, and below is a video of the performance.