Ryan Wiancko reads aloud, "Fun is Fine: Toward a Philosophy of Game Design", which inspired my research into serious uses of games. Ryan's serious voice is particularly appropriate for this topic: Some games are important cultural experiences that portray the human condition and elevate the minds of their players. You may listen to this and other lucid designers, free to download at Industry Broadcast.
(The author's introduction causes me to chuckle and blush, because 2003 was before World of Warcraft and many newer MMOs.) The article grew out of a dialogue on MUD-Dev, so I'd be happy to hear your opinion on the topic.