pandora: build your own radio station with no dj chat!

It's been posted before, but...
pandora.com
While I've only listened to this at a friend's, and it's pretty cool: the software builds up an idea of the kind of music you like and it's a great way to find new stuff
It has this really fun function where you can enter two genres/musicians and pandora finds stuff that links them.
Reggae and metal? Classical and bluegrass?