Most kids (and plenty of parents) like to build - forts, castles, towers, model airplanes, and more - which explains why there are so many products out there designed to help us do just that. They range from simple wooden blocks and kits that show us how to construct all sorts of cool things using objects that we have around the house, to the most complex building sets. There's a wonderful sense of accomplishment that one gets from stepping back and looking at a completed project. Most of the time, though, that's about all you can do with it. But there's a special thrill that comes from seeing whatever you've built come to life: electrical projects that turn lights on and off, radio kits that receive real broadcasts, and, of course, anything that moves. This week we're taking a look at two very different construction sets that will provide hours of parent-child entertainment, both during the actual assembly process and afterwards, when it starts to move.