Did a search nothing came up.
Link, clicky clicky.
Ends October 24th. This is a really good deal, especially considering you get both DLC's. It cost me $10 for the full game and all DLC on the xbox... And that was with a 50% off everything.
The game is GFWL enabled (Has xbox achievements). The achievements ARE STACKABLE. This means, if you buy the PC version IT HAS A SEPARATE SET OF ACHIEVEMENTS! What does this mean? A higher gamerscore!