One of my favorite after school activities as a kid was playing with Lego’s Mindstorm robot kits — if your kids have any interest, it could be a fun (and productive imo) way to have your interests meet in the middle :).
The irony is that he owns about €1000 of Lego bricks. He spent half his first communion money on Lego (€300), we made him put the rest in to the credit union. Since them he has told us he has become atheist as science makes more sense, but he'll still do his confirmation to get more money to buy Lego. Hmm....