Sunny Days on "Sesame Street"

Since "Sesame Street" first aired on Nov. 10, 1969, the show has been bringing sunny days and important lessons to children around the world. The original cast is seen in this photo.

Big Bird is one of the show's most beloved characters. The towering, yellow-feathered 6-year-old has called Sesame Street home since the show began. He even appeared solo on the cover of Time magazine, who dubbed his show "TV's Gift to Children."

Elmo, seen here with two firefighters, is another one of the show's most beloved characters. He made his first appearance on the show in 1972, as "Baby Monster." He didn't receive his current moniker until 1985. Since 1998, he has hosted "Elmo's World," a segment aimed at toddlers that airs during the last 15 minutes of "Sesame Street."

"Me want Cookie!" is one of Cookie Monster's most famous lines, but as time has passed the character has begun to watch what he eats. He explained his new philosophy on Martha Stewart's TV show in 2007, telling her that cookies are a "sometimes food."

Roommates Bert and Ernie, seen here in 2006, share a basement apartment at 123 Sesame Street. Ernie was originally performed by Jim Henson until his death in 1990, and Bert was voiced by Frank Oz until 2001. Ernie's love for his rubber duck was immortalized in the song "Rubber Duckie," which hit No. 16 on the Billboard Hot 100 in September 1970.

Other countries have co-produced their own unique versions of "Sesame Street," which include characters and segments that reflect their country's cultures. Other countries simply air dubbed versions of the original "Sesame Street." Seen here are characters from China's "Zhima Jie," from left, Hu Hu Zhu, Da Niao (Big Bird) and Little Plum.

The 2004 cast of "Sesame Street." Over the years the cast has grown, adding human and pupper characters alike. The show has also seen many celebrity guest stars, including Bob Hope, Julia Roberts, Ellen Degeneres, Johnny Cash, Barbra Walters and Lena Horne. First lady Michelle Obama is also joining that list - she's set to star on the 40th anniversary show airing on Nov. 10, 2009.

Caroll Spinney, the puppeteer who plays the roles of Big Bird and Oscar the Grouch on "Sesame Street," arrives with Oscar the Grouch at the 33rd Annual Daytime Emmy Awards in Los Angeles, on April 28, 2006. Spinney has played both characters since the show began in 1969.

Oscar the Grouch, left, and Telly Monster, of the children's television show "Sesame Street," perform at the Daytime Emmy Awards on Aug. 30, 2009, in Los Angeles.

Elmo, of the children's television show "Sesame Street," arrives at the Daytime Emmy Awards on Sunday, Aug. 30, 2009, in Los Angeles. The show received a Lifetime Achievement Award at the ceremony. "Sesame Street" marks its 40th anniversary this year.

"Sesame Street" executive producer Carol-Lynn Parente, left, and cast member Sonia Manzano, center, and Big Bird accept the Emmy Lifetime Achievement Award at the Daytime Emmy Awards on Aug. 30, 2009, in Los Angeles. As of 2009, the series has received 118 Emmy Awards, more than any other television series.

Cookie Monster, center, eats the statuette given for the Lifetime Achievement Award for "Sesame Street" at the Daytime Emmy Awards on Sunday Aug. 30, 2009, in Los Angeles. As of 2009, an estimated 77 million Americans watched "Sesame Street" as children.

This May 5, 2009 photo released by Sesame Workshop shows first lady Michelle Obama, third from left, with Big Bird, Elmo, Muppets & cast in "Michelle Obama Plants A Garden" in Astoria, N.Y. Mrs. Obama appears on "Sesame Street" Tuesday, Nov. 10, 2009, on the 40th anniversary of the show's premiere.