In the NYT, there is a good article by Clive Thompson about serious games or the inherent potential of games to be learning platform. Some excerpts:

Games, they argue, can be more than just mindless fun, they can be a medium for change. (...) “What everyone’s realizing is that games are really good at illustrating complex situations,” said Suzanne Seggerman (...) Henry Jenkins, an M.I.T. professor who studies games and learning, said the medium has matured along with the young people who were raised on it. “The generation that grew up with Super Mario is entering the workplace, entering politics, so they see games as just another good tool to use to communicate,” he added. “If games are going to be a mature medium, they’re going to serve a variety of functions. It’s like with film. We think first of using it for entertainment, but then also for education and advertising and politics and all that stuff.” (...) This is the central conceit behind all these efforts: that games are uniquely good at teaching people how complex systems work. (...) But do these games actually work? Even proponents admit that it’s still difficult to say. “These things are just at the prototype level,” Professor Jenkins said. “We’ve just got one classroom here, one classroom there, where we’ve documented some benefits.” And without more studies documenting the effectiveness of the games, he said, “oxygen’s going to be sucked out of this.” (...) “Ultimately, a video game is just another medium for artistic expression,” he concluded. “Which is why I like this game in a weird way, because if you are going to play games, why not learn something important in the process?”

The article is also full of examples of this types of games.