Combine Turntable.fm 's crowd-rated DJ setup with Chatroulette , subtract the 50,000 naked dudes , and sprinkle in some 8 Mile  and you get Detroit-based Rapt.fm , a real-time platform for aspiring Eminems. On Rapt.fm you can battle with a friend or a stranger to impress an audience of avatars who can dole out "props" that help up your Hype Meter status.
Rapt.fm is still in private alpha for now, so it's impossible to say how sustainable rap battles are for business. Then again, there's good reason to be skeptical about the viability of a site that closely resembles aspects of two services that famously peaked early, to investors' dismay (see: "Turntable.fm: Where Did Our Love Go?"  and "The Decline And Fall Of Chatroulette ").
[Image: Flickr user Robert Bejil Photography ]