Codemasters removed Demolition Derby from GRID 2 and annoyed a lot of people in the process I think, but they have now rectified that.
They revealed today that they have now released it for GRID 2 in the form of free DLC for PC and Xbox users this week, with the PS3 version coming next week.
The DLC will include the Jupiter Eagle Ray Mk 5 Demo Derby car with a range of stock liveries, and a customizable one. There will also be the Detroit Demoltion Stadium where you can choose from two configurations of the track, both including a cross-over section.
The demolition derby pack is the latest in a long list of "community updates" that Codemasters are currently putting into GRID 2, which you can read all about over on their blog.