I actually watched that podcast last week! Are you going to be making more? I think my dump-truck would have been robotics, it was something I liked reading about and I would come up with all sorts of ideas for stuff I could make if I could just have had a Lego Mindstorms kit. I subscribed to Real Robots magazine which came with parts to build a small (and very stupid) robot. There was some problems with the company and they mucked everything up, eventually we just cancelled it -- I am actually surprised there was so much more released after we stopped, and am very sad that we stopped before the programming phase as that was what I was interested in. I have since left robotics behind, it's always been that path I'd have liked to take and I hope to be able to work some of it into teaching.