Building "Smart" dominos with sensors and circuits

This looks like fun, and actually seems simple enough that even someone with a fear of wires could put together a pretty competent smart-domino setup. And it’ll give you a reason to go dig around in your parents’ basement for those old legos you secretly want to have around anyway. I like the marble circuit-break. The whole thing reminds me of stuff like The Incredible Machine and Armadillo Run.