Games that teach: Code Combat = Tower Defence clone where instead of just placing towers … you write basic commands in javascript to manipulate your troops around the map:

This is an early preview build, so it ONLY WORKS WITH CHROME (EDIT: (deleted off topic personal commentary) … Chrome’s native plugin stuff is great, I can see why a lot of devs use it for prototyping … but the politics around Google, and their actions to edge-out more inclusive, free, open browsers is distressing)

Screen Shot 2013-06-10 at 19.36.04