The season on the whole has been womp womp with a few highlights. But I loved this episode. I'm a big Muppets fan, and the songs were beautiful. In fact, I've been listening to them over and over and over. You can too:
But there's more than just being charmed by the puppets and the music. (And also that the puppets aren't used just for the hell of it: there's a reason, grounded in what happened to the group.) This episode is as important to the canon of the group as Competitive Ecology. or Cooperative Calligraphy.
They recognize they're doing what they always do so they go outside their comfort zone and something terrible happens to them. This will reenforce their need to stay safely in the study room and fall into their safe comfortable patterns. Perfect addition to this self-aware sitcom. It's as though the "Cheers" gang decided to go on safari and Carla got attacked by a hippo. They'd say, "Whoah, we'd better just stay in the bar where it's safe from now on."
There's also the matter of the secrets. I think the little Indian princess story Jeff told Abed is a more dark secret than the one he told the group in 409. What's more, that story plays into the group's expectations of him, since they all seem obsessed by his relationship with his dad (I hate the way they seem to hit this on the nose in every episode). If Abed did confess a secret, and if he remembers the secrets of all the others, then he alone knows Jeff is lying about his secret. Jeff is the one who suggested they start confessing in the light of day; he got the ball rolling with a story that conveniently fits into what the group already thinks about him. Abed may be keeping Jeff's secret secret as well as his own.
I wish there had been something other than a fire in the cafeteria, since we already had one of those last year and we also had Troy confessing to starting a fire. I wish the Dean hadn't worn a Pinnocchio costume. And I wish Jeff had a better zinger for the Dean than "shut up." But on the whole, this episode is worthy of the show I love so much.