Judging by our basement, a happy 10-year-old boy lives in our house. I wish. Then we could rummage through the Lego sets, the Erector sets, the Snap Circuits, and the Kinex. My favorite Lego set, the King’s Castle, model 6080, I bought at a yard sale when Duncan was still in diapers. I assembled it while he napped: a test run.