I recently came across this summer program for high school kids that aims to teach robotics and programming. The course had a few interesting items planned like designing a line following robot, obstacle avoidance robot and a rescue robot. But the students had to one up their teachers/mentors to show that they are the future and came up with robots that were nothing but phenomenal.
Let me introduce you to a robot that can avoid falling off a cliff. This robot uses the accelerometer on the Pololu Zumo bot to understand the slope (downward or upward) and take corrective measures so that it can stay on top of a board.
The next one is a robot that solved a maze. This robot uses the reflectance sensor to follow lines and what looks like an IR distance measurement sensor to move from start to finish. The interesting aspect was the fact that the robot does not seem to have any memory about the track and still ends up solving the maze. Enjoy the video -