A marble run set. Yup-yup-yup. DD played endlessly with one of those, trying all kinds of different things...
We bought the Quadrilla Twist set recently and DS is loving it.
What about searching YouTube for construction project videos, choosing a DIY project, sourcing materials, and following through. He might like woodworking, in particular, and there are lots of maker shops around that supply the tools. Wood is such a versatile material, and I remember the pride I felt as a child building real things to use, like a desk and a stool for at the counter. Heck, as an adult, I'm proud of some custom furniture DH and I designed and built together when we were first married.
He could also buy an old junker bicycle and fix it up.
