The American Psychological Association has released a study of surgeons (why they chose surgeons to study, who knows) that says surgeons who play World of Warcraft and other video games can make them a better surgeon overall. Not only does controlling a game character give you better motor skills, but playing an involved and complicated game can, not surprisingly, can make you a better analytical thinker and problem solver. Surgeons who played videogames (though they don't mention how much or how often) were faster at advanced surgical procedures and make fewer errors than surgeons who didn't.
So does this mean that playing videogames can replace education entirely? Not so fast, back to schoolers -- apparently playing games also makes things not so complicated seem not so interesting. While leading a pickup group in Karazhan will definitely help your problem solving abilities (though probably not your stress levels), it will make it harder for you to do things like settle down and study a book. As with everything, moderation is the key.