Immune Attack... Attacks!
The Federation of American Scientists (FAS) decided that technology could be used for education and soon developed a game for teaching in the form of Immune Attack. The game is a third person Fantastic Voyage into InnerSpace where you control a nanobot attempting to save an ailing patient and teaching you about your own internal biological systems in the process. A beefy download at almost 600mb, the game is actually interesting and not just something to trick the kids with.