Steal this music
If you haven't heard, you should. First Jay Z released his supposedly final Black album and included an a capella disc. Then people started doing what they do if you leave that sort of thing hanging out. Hence came DJ Dangermouse's "The Grey Album", a mix of the great beyonce rider's Black album and the Beatle's white album, which inspired a video and a host of other mashups. I'm rocking "Jay-Zeezer: The Black and Blue Album" right now.
Also, I have to mention the Kleptones and their "A Night at the Hip Hopera" which should make Freddie Mercury smile, if not his estate's lawyers.