My young daughters (9 and 11) and I have built a new robot we call "Spirit II Mars Rover" in honor of the rovers that are on Mars. The most interesting thing about this robot is its unique suspension system and how it turns, so be sure to watch the video on this robot's page: http://beatty-robotics.com/?p=525. My daughters and I have built more than ten Arduino-based robots so far, which you can see here: www.beatty-robotics.com