My CT 871 class has me writing programs using eToys. It's a menu driven programming language and is pretty good at letting help kids write applications that demonstrate what they know. Kids can write games or simulate physcial systems, like orbiting planet or bouncing balls.
For my final project, I'm writing a simulator for the CheapBots. The simulator lets a person control the H-Bridges of the robot in order to drive it around. In other words, the user acts like the robot controller. Future abilities of the program will let users observe the responses of the CheapBot Line Follower as the robot drives around.
The software is free at www.squeakland.org