DARPA's created what it's calling the Iron Curtain, which is a system that mounts on top of a Humvee and takes out any rockets shot in its direction. It's pretty nuts.
They've been working on these Active Protection Systems for a while now, but this is the first that works on a moving vehicle. It uses radar, optical sensors and some other secret elements to detect projectiles. It then destroys them right before impact, creating an explosion but one that is much less harmful to the vehicle.