This is old news, but it seems like I'm living in a box, since I just stumbled upon it: SpaceChem. A game where you create visual programs in order to manipulate chemical elements and molecules. In space. It's a tough game, and I love it.
Reminded me a bit of Manufactoria, which is also great.
Just wanted to share, and ask if anyone knows any other good games that require you to actually write (visual) programs.