Sphero

I got the boys a Sphero robot (and they pooled their $ together and bought themselves another one).  I've done my best to keep it from being just another remote-controlled toy.  So we made an obstacle course and had the challenge to get the Sphero to make it through the course.  Fist they had to find a relationship between the distance it traveled and length the motor ran for a certain speed, then write the code to make it go through.  This video is one of the failed attempts, and I can't find the video for a successful attempt: but you get the idea.  I had to really walk them through this.  I'd like to just give them a challenge and let them take it away, but I haven't been able to make a challenge that they care about enough yet to not just do it with the remote-control option.  Darn remote-control option!