Big Bird, Oscar the Grouch, Bert and Ernie, Elmo and Grover have something to celebrate. Sesame Street, their fictional New York borough, and the television show probably responsible for everything you knew as a kid, turns 40 today.

Created in 1969 from the psychedelic mind of puppeteer Jim Henson (back in the freewheelin' '60s, when puppeteering could actually be a career), Sesame Street is now the longest-running children's television program in history, broadcast in more than 20 other countries and several different language. In the United States, it's still funded by the non-profit organization Sesame Workshop, formerly the Children's Television Workshop.

The show's creators always viewed the program as an experiment, which allowed them to push the envelope by bringing actors and musical guests well-known by parents into the world of their fans' children. Musical director Joe Raposo, reportedly the inspiration for Cookie Monster, used his connections on Broadway to encourage musical guests to participate in the show.

Sesame Street was one of the first programs to combine research with television production and as a result, was the first children's program with a set educational curriculum. The creators discovered that children learn better when their lessons are paired with music.

What followed was a rich tradition of serious artists toning down their message for children; everyone from Johnny Cash to James Blunt has sung with the Muppets. Executive producer Carol-Lynn Parente told the Ottawa Citizen that guest stars from pop culture help the show stay current.

After the jump, ten of Rocks Off's favorite musical performances from the land where the air is always sweet.

Kids love nothing more than to jump and jive, right? We can hardly believe Calloway was still alive in the era of Sesame Street, but here he is, gravelly voice, tails and all.

Charles sings Kermit the Frog's outsider's lament.

Only the Man in Black could take on the Grouch in Green.

The kids are loving it. Check out the tiny headbanger on the balcony!

Okay, Rocks Off knows Elmo is just a piece of furry fabric and wires, but this sweet lullaby makes us get our cheese on.

Did Paul Simon just cut that little girl off mid-song?

Put a squid on it. Goofiness ensues!

Feist helps the monsters count.

DC teaches Elmo, Grover and Zoe a new way to walk. Okay, this one's pretty bad.

R.E.M. sings "Furry Happy Monsters" with a wild bunch of Muppets, including a Kate Pierson look-alike.

Little Richard sings Ernie's ode to his bath toy.