This is the Acer, a 4,500 pound robot tank designed to withstand pretty much anything, including a bomb exploding right underneath it.
This thing can run for 18 hours, using "behavior engine" AI to drive itself around (or be controlled by a human on board, but that's boring). It's AI responds to the environment around it, allowing it to adapt to new situations when completing a mission.
Of course, in order for this to be of any use, the Army needs to order some of them, which they haven't done yet. With the wars in Iraq and Afghanistan winding down, they probably don't feel like dropping tens of millions of dollars on new tank robots that they don't really need.
Via Danger Room