An Xbox Webcast program. Something like SAM for the PC. Just a program that will run on the xbox and enable you to broadcast mp3's on a radio station. That would own.

Well, there are open source clients that you could easily modify to match or fit the xbox's API and then compile it into an XBE. I'm assuming that's all there is too it but I might be wrong because I've never look into what libraries are supported when coding for the xbox and what not.