Just a word of warning, you can't mod games on Xbox 360 or the PS3. These mods only apply for the PC version of the game.
Mods? 
Yeah. They're basically downloadable content to add new skins and levels to the game. Check the links I posted in the journal for examples.
That does sound very interesting, but I'm sure I'll be able to enjoy the Xbox 360 version of the game nonetheless. 