Teaching people to type with video games.

This is an excellent example of how you take a mundane task and turn it into a game.  Typing skills are crucial to anyone who uses a computer.  The people at phoboslab.org have a neat little game reminiscent of Asteroids, except that you must words on your keyboard to fire your lasers.  Sure it seems like a game when you play it, and it is! However, every time you play, you are really practicing your typing skills.