Zon: Chinese language learning MMO
This is cool: an MMO devoted to language learning via full immersion.
Zon is an unique interactive massively multiplayer online role playing game for learning Mandarin Chinese.
By interacting in the Zon environment you will be exposed to Chinese language and cultural knowledge in a new and exciting way. Everything that you do in the game is another chance to learn new words, phrases and cultural info about China. Never before has learning Chinese been more fun.
Not at all the first time this has been tried, of course; at SOE we supported a few college campuses that were doing full-immersion language learning via EQ2, for example.

Mm. I think they’re doing something interesting in that rather than just use the world as a method of immersion, there’s also an attempt to deliberately use it as a teaching tool as well. Using EQ2 as an immersion tool is interesting and all, but it’s not built for it, so it won’t have the necessary language tools out of the box. You still need the teachers and the textbooks so you can get enough of the language to be able to go from there. This seems like it could replace the need for the teacher and the textbook entirely.
Obligatory link to Penny Arcade:
http://www.penny-arcade.com/comic/2008/5/12/