Hmm... Not sure, since there are a couple of threads for people to post their own made-up Muppet characters. A game where those characters were to interact with other more established Muppets would be feasible, though that's more the realm of the fanfics and the town of Hensonville around the dorms. Granted, the town doesn't get explored much... Maybe that could serve as the focus of a new RPG, themed for either September or October, where the object is to go trick-or-treating all around?
Think on these suggestions, hope it helps.