Over at the Crackdown forums, a staff member posted a teaser image of some new downloadable content. When is it coming out? "Soon," he says...

And that there's going to be a "new game type and a new type of vehicle."

The posts following that one speculate that it's a four player racing game mode, and that you'll be able to use guns.

My speculation? It's not the next Mario Kart, but the game play mode is most likely on some kind of drug. Probably crack. And it has something else involving the angle "down."