The above video you see is the Apple TV OS running off of an external hard drive. How? Well after a little DIY action and cracking open the Apple TV, someone dumped the contents of the drive, modified some files, and loaded it up via an external USB drive hook up. It appears to work just fine, though we don’t get why you’d want to run the Apple TV OS on another Mac, since other Macs don’t, ya know, come with component and HDMI hook ups, etc. There’s also a guy who loaded the Apple TV OS on his Mac Mini directly, but there’s still some issues.
This just goes to show you how Apple fans love them some happy hacking. Too bad the Apple TV OS is just a glorified Front Row or I’d be somewhat excited. If you’re looking for a copy, just hit up the torrent sites and do some digging.