Check out this video. Microsoft wants to use your existing iPhone / iPad / Android to power their entertainment portal via an XBOX. It's interesting that they are opening it up to whatever mobile device you own and not making you stick to just one tech eco system like my beloved Apple does.
The core component will be the XBOX of course but they are actually impressing me with their open push for integrating with your device you have now. I could see adding my XBOX into the living room entertainment system. There is a drawback though, the XBOX is just plain loud. Unlike the perfectly silent Apple TV.
Back from vacation