When Pandora blocked access to Canadians, I built a streaming music service ala seeqpod, which did auto playlisting like pandora.

The music analysis stuff was really time consuming and expensive and of course wasn't nearly as good as Pandora, so I canned it, but had this left over code that crawled the web looking for music.

I did a few quick changes to the code so that it grabbed concerts instead of music, and voila, http://HearWhere.com