Good little video, courtesy of Trossen.
This video demonstrates learning by example in an artificial neural network that controls the motion of a mobile robot. The robot uses four sonar sensors and three IR sensors to detect the ranges to nearby objects. A wireless controller is used to initially remote control the robot past some test objects while the robot records the sensor readings and motor control signals. This data is then used to train a 2×7 artificial neural network (2 motors and 7 sensors). Once the network is trained, it is used to control the robot without intervention from the operator.