Uh oh - turns out Stephen Colbert was on Sesame Street as the letter Z.
And Jon Stewart also did a bit on Sesame Street.
Robin Williams was apparently on six times. Here's one:
Bill Cosby was also on several times:
Oh joy - I found one of my favorite all-time bits from Sesame Street. Featuring my favorite muppet Grover:
The dialog kills me - Grover keeps coming up with freakishly specific descriptions of the sound (the game show is "name that sound") only to have Guy Smiley ask him to be simple:
Here comes sound number two.
(sound of dog barking)
Yes, yes. Ah, well let's see, I can tell you that uh, his name is Rover, and that he loves bedroom slippers, and uh, it is an Afghan mixed with Andalusian Lhasa Apso.
I beg your pardon?
GROVERI literally haven't seen this for over thirty years, since I watched it with my daughter when she was a baby. But I always remembered the gag. Glad I got to see it again.
It is a doggy.