Pretty good episode, considering it was sorta a "this is this and that is that" type episode explaining nature, though briefly.
Anyway, here are the highlights...
Baby bear singing "I Love to Sing in the Shower" (I thought he was domesticated and lived in a house, tho)
The return of Stinky the Stinkweed (he wasn't on the show for a while, but that's a'ight...)
Cookie Monster's brilliant parody of It's rainin' Men.
Oscar AND Big Bird in the same episode (though, not in the same scene).
And a new Super Grover 2.0
Other than that, at least the reused stuff predates wideframe for the most part... still not happy with that "Jump Up" song.