Not exactly a Junkbot but definitely related is the Robot Obstacle Course game developed by Oregon Museum of Science and Industry. The game takes the player through exercises in Boolean Logic to allow the robot to collect keys and jump over traps to open the door. This a good and fun introduction to logic.
To play the game go to: http://www.omsi.edu/tech/RobotActivity/index.htm
If you would like to know more about the Junkbots project contact firstname.lastname@example.org