Carmageddon: Reincarnation is still in Steam Early Access, but if you want to buy in on the ground floor, you can pick it up for £9.99.
Better yet, you'll get Carmageddon 1 and 2 for free.
It's always tough to recommend Early Access games, seeing as there are no guarantees. However, our ex senior-editor thought this was an absolute riot and by most accounts it's shaping up to be as anarchic, gory and satisfying as its infamous predecessors. Don't invest yet if you're not entirely sold, however. Thanks BigKenneth!
Here's a very early hands-on video - bear in mind that the project has likely come on in leaps and bounds since.