The Defense Advanced Research Projects Agency (DARPA) funds a variety of projects for the Department of Defense. The projects range from self-driving cars to crazy space vehicles, but their mission is to prevent a "technological surprise to the U.S."
Based on the fear of Sputnik in the 1950s, DARPA has a continuing legacy of cool science and technology projects. This walking robot is one of their more intriguing developments. At 0:27 you can see a man push the robot, but it resumes walking freely. Very advanced stuff! via Devour