The Nao humanoid robot is quite fascinating to play around with. It has various sensors and is programmable. You can use it to learn about robots and programming. As the below video shows, you can also play rock paper scissors against the robot. The robot tracks the player with its built-in camera and recognizes the gesture.
This is a lab project by Laurens Heinje and Robert Rudolph from Humanoid Robots Lab, University of Bonn.