Real-time programmer Jack W. Crenshaw has written a fascinating, if not directly robotics-related, article on the differing opportunities for learning by doing that exist for kids today compared to a generation ago. Jack learned by taking apart model trains, clocks, and the Sturmey-Archer 3-speed hub from his bicycle. But how could someone growing up in today's world learn about computers in the same way? He goes on to describe toy-like machines that implement digital principals such as flip-flops, counters, and logic-gates in a mechanical way that allows you to see, touch, and disassemble them. He doesn't mention it in his article, but I think robotics kits offer kids some of the same opportunities to take apart and understand modern machines.