Apple TV Booting off External USB
After initial reports of hacking the Apple TV to play other formats such as XviD, work has continued surrounding the original Something Awful forum thread about how to get further functionality out of the Apple TV.
Users have been able to run various apps (World of Warcraft, VLC, Firefox) remotely through VNC. Other efforts reveal that the Apple TV does respond to an external keyboard.
The most significant step at this stage has been the ability to boot the Apple TV from an external USB drive. A video demos the external USB drive on an (essentially) unmodified Apple TV.