Henry Lowood, a Library Science teacher at San Jose State University recently took his online "Games and Libraries" class on a virtual field trip: into World of Warcraft. As he explains it on the How They Got Game 2 site, the lesson he was teaching dealt with the usefulness of online games in the library, and his students for the most part had no exposure to online gaming, and so the class logged in for class credit.
They started their own guild on the Windrunner realm so that they would have their own chat channel, and had to deal with the issue of mass death since most of the students were using 10-day trial accounts and thus were too low level to survive long. Despite the challenge, the online forum proved a successful environment in which to teach, and within WoW the students were able to encounter the community of online gamers, witness their teacher (a paladin) duel a priest to illustrate the PvP aspects of the game, and even received some resurrection from their instructor when they died along the way, "a first in terms of faculty-student relations."
Now, those of us who have taught know the difficulties of keeping a classroom of students engaged, so I think this is a pretty novel way to do so. It helps that the lesson was specifically about online gaming honestly, but I wonder how well this would apply to a discussion on say virtual storytelling, or even a history lesson on warfare. I know that would be one class session my students would have never skipped out on.