I am thoroughly jealous of your time in the shop with the grandchildren. There isn't anything I can think of to be more grateful for. My shop is available, but I travel for work. It has allowed me to see and experience a great deal, but has made me miss out on so many other things.
This is an old thread, but an interesting one. I recently purchased a few pen making kits for 11 and 8 year old boys.
I like the nut and bolt idea better. It will be our first project. We also have some old Star Wars models to assemble this summer. I have an early Millennium Falcon model and...