Apple's set-top box, the Apple TV, runs a modified version of Mac OS X - this we've known for a while now. However, hackers have figured out how to transplant the operating system from the ultra-slim Mac - if the cap fits... - and run it on a MacBook laptop.

Not that this is meant to happen - the hack requires a patched version of the Apple TV's incarnation of Finder, which would otherwise do a hardware check when it starts up, we presume. Downloading said patched Finder is, of course, entirely dodgy, so don't ask us where to find it, OK?

The Apple TV also uses a couple of altered Frameworks - think plug-ins for the OS - to connect it to iPhoto and to introduce BackRow, a partner app for Mac OS X's media centre UI, FrontRow.

The rest of the Apple TV's OS matches the standard Mac OS X install - or at least the two versions close enough to be interchangeable.

The process is explained over at AppleTVHacks, which has pics a-plenty and a movie of said MacBook booting from the Apple TV:

The site's a mine of information, including a guide to upgrading the Apple TV's 40GB hard drive to a more capacious model and details of running useful code like Remote Desktop, the Apache web server and VLC on the box.