Bert and Ernie are two roommates on the long-running television show Sesame Street. The two appear together in numerous skits, forming a comic duo that is one of the centerpieces of the program. The characters were originated by Muppet creator Jim Henson, and originally performed by Frank Oz and Jim Henson

Bert, though intelligent, is also grumpy, boring and easily frustrated. He enjoys activities such as paper clip and bottle cap collecting, cooking oatmeal and watching pigeons. Bert is good friends with a pigeon named Bernice, and has even created a dance called "Doin' the Pigeon".

Ernie is well-known for taking baths with his Rubber Duckie, and for having trouble trying to learn to play the saxophone because he would not "put down the duckie". Ernie's performance of "Rubber Duckie," wherein he sings affectionately about his squeaking toy duck and the joy it brings him during bathtime, became a modest mainstream hit, reaching No. 16 on the Billboard Hot 100 in September 1970.

A typical Bert and Ernie skit follows one of two similar patterns, both beginning with Ernie devising a hare-brained idea and Bert calmly attempting to talk him out of it. Usually this ends with Bert losing his temper and Ernie remaining oblivious to his own bad idea. Sometimes Ernie's idea miraculously turns out to be correct, much to Bert's evident frustration.

An example of a Bert and Ernie skit is the banana in my ear joke:
Bert: "Hey, you've got a banana in your ear!"
Ernie: "What?"
Bert: "I said, YOU'VE GOT A BANANA IN YOUR EAR!"
Ernie: "What? I can't hear you; I've got a banana in my ear!"

According to A&E's Biography, Ernie and Bert were basically the only Muppets to appear in the Sesame Street pilot episode, which was screen tested to a number of families in July 1969. Their brief appearance was the only part of the pilot that tested well, so it was decided that not only should Muppet characters be the "stars" of the show, but would also interact with the human characters, something that was not done in the pilot. 

Please enjoy this clip of Bert and Ernie: