Feeling a bit nostalgic, I looked for, then eventualy stumbled upon, a lot of Sesame Street videos on YouTube that I vividly remember seeing as a kid. Here are my favorites.

Crayola Crayon Factory

Pinball

I'm still waiting for a Phish cover of the song

Alligator King

Superstition by Stevie Wonder

Teeny Little Super Guy

Lost Boy Remembers His Way Home (I thought it was creepy then, and it's still a little creepy now.)

Orange Sings Carmen

Cab Calloway Sings "Hi De Ho Man"

Ladybugs' Picnic

Red Ball 1,2,3

Goat Gets Mad

And some new favorites, linked since embedding was disabled on many of these:

Neil Patrick Harris is Sesame Street's Shoe Fairy

Preschool Musical

Feist Sings 1,2,3,4