In the late 80s, Tad McGeer invented the concept of passive dynamics. While doing graduate work at Simon Fraser University, he built a robot that could walk down a plank without power, sensors, or a control system. The robot was built from metal rods, springs, and weights in just the right configuration such that the legs and arms would swing in a coordinated way as it ambled down. It was also able to walk efficiently on a flat surface by giving it a small push. In 2001, Steve Collins from Cornell University build a passive walker based on McGeer's original model shown in the video below.
The idea of adding power to passive dynamic walkers later inspired other universities to develop their own versions. McGeer demonstrated that a bottom-up approach to robotics must begin with the body. A cleverly designed body can remove the need for high speed computers to control all the leg movements. This approach has still not been widely accepted. For instance, Honda's Asimo Robot which after 20 years of research and at a cost of $1 million per unit still uses a bulldozer approach of scanning and conquering the environment instead of dynamically interacting with it.
(The video and this description come from http://skitterbot.com/blog/passive-dynamic-walkers/. I uploaded it again just because it was no longer working at the original location.)