It usually doesn't take long after a highly-anticipated device comes out that someone takes it apart, and modifies it to do things that it normally wouldn't do.
The Apple TV is no different. With this simple (and by simple I mean rather difficult) hack, you can modify your Apple TV to play DivX files. Granted, you might (will) void your warranty, but that's the way life is when you're hacking and modifying things as such.
The guys that brought us this hack have also confirmed that it is running on a stripped-down version of OS X which makes things rather easy for would-be modders.
Hackers Hack Hacked Apple TV to Play DivX [via crunchgear]