Nov. 10, 2009 -- "Sesame Street," the beloved children's show, turns 40 this week. The longest-running show in children's television history, whose fuzzy, lovable muppets are now seen in more than 140 countries, revolutionizing children's television. "Sesame Street" became the first show for kids that had education as its guiding principle and used the power of TV to teach.
Today is the season 40 premiere, but Google.com celebrated early, including Big Bird's feet in the "Google Doodle," the icon on the site's homepage. Bert and Ernie, Cookie Monster and Count Dracula also graced the site.
And the show is pulling out all the stops, planning a season filled with celebrity appearances, by Cameron Diaz, Sarah Jessica Parker, Kobe Bryant and others. First lady Michelle Obama will plant a garden with Big Bird and Elmo, pushing a new focus on nature, the environment and "green" issues.
CLICK HERE to see Sesame Street's stars and celebrity guests through the years.
But since the series premiered in 1969, "Sesame Street" is no longer the only game in town. More and more kids are drawn to cartoons like "SpongeBob Square Pants," or options on the Internet, making it more difficult to captivate the newest generation of young viewers.
But for the staff at "Sesame Street," adapting to the times and changing technologies is nothing new. It has broadened its target audience, adding new characters and tweaking the format each season.
"The thing that keeps 'Sesame Street' on the air is that we are constantly evolving with the times," said Executive Producer Carol-Lynn Parente. "We start every season with a research seminar. We bring educators and experts in to tell us what the needs of preschoolers [are] today. And that today has changed from the 20 years since I've been here and certainly over the 40-year span of the show. The show is vastly different than the 'Sesame Street' I watched as a kid."
The show's cast of characters has undergone makeovers. The original Oscar in 1969 was orange. Now, the grouchy, trash-can muppet is the more recognizable green. The lovable and ticklish muppet Elmo was added to the show in the late '70s to appeal to its younger audience.
Sesame Street Set: A 'Real Community'
"One of the main reasons Elmo was put on the show was that they found out how young the kids were who were watching the show .. .and they needed a younger character," said actor Kevin Clash, who has been the voice behind Elmo since 1983. "When I first started performing, Elmo was more primitive -- 'Elmo do this, Elmo do that' -- but now he speaks in fuller sentences."
"Sesame Street" actors have also aged over 40 years. When Will Lee, the actor who played Mr. Hooper of "Mr. Hooper's Store," died of a heart attack in December 1982, "Sesame Street" used it as a teaching moment. Rather than sweeping it under the rug, it was written into a 1983 episode in which Big Bird learns about death.
"'Sesame Street' is this real community where people of all backgrounds live together and work together and when the actor died, it seemed that there wasn't any other way than to deal with the truth in a straightforward manner," Parente said. "And that's what so special about 'Sesame Street.' It doesn't talk down to kids, and it respects them as little adults."
Rosemary Truglio, a developmental psychologist and head of research at Children's Workshop, the nonprofit organization that oversees the educational content for the show, said they strive to make the program appealing and entertaining for kids.
"We go into the school environment and observe them watch the show. ... We know we could have the greatest curriculum, but if the child is not connected and it's not appealing, the child isn't going to be exposed to the content," Truglio said. "So we're looking for appeal and participatory behavior and comprehension -- are they understanding the lessons."
"Nightline" visited "Sesame Street's" studios, where Golden Globe nominated actress Maggie Gyllenhaal was filming the "Word on the Street" spot for the show, which is aimed at building kids' vocabulary.
While 4-year-olds in the audience don't know Gyllenhaal, or most of the show's other famous guests, there's a real science behind having celebrities guest star. Experts said it encourages parents to watch the show with their kids -- and that's the take-home message.
Sesame Street Spoofs 'Mad Men,' 'Sex and the City'
"The show has always been written on two levels by design from the very beginning to grab the adult viewer in and as an educational show the learning goes so much deeper when there is co-viewing," said Parente. "The vocabulary curriculum extends to a food shopping trip and labeling foods."
The "Sesame Street" set evokes a feeling of family. "Nightline" spoke to Cheryl Henson, daughter of famous puppeteer Jim Henson, who was a driving force behind "Sesame Street" and also founded the Muppets.
"It's really marvelous to be here today. I got to greet Frankie the cameraman from the very first season, shooting for 40 years," said Cheryl Henson, who grew up with the show. "Many of the people are the same. It's wonderful to see them. As soon as I came here I wanted to hug them."
"Sesame Street's" capacity to stay relevant falls largely in the hands of the writers, who have to walk a fine line between being entertaining and educational. For the 40th Season, the show will do parodies of popular adult shows like "Mad Men," "Sex and the City" and more.
"I think the goal is to entertain everyone. Entertain the kid and keep the parent in the room," said Joey Mazzarino, head writer and a puppeteer. "I have a 3-year-old, and I watch a lot of TV with her and sometimes it's hard for me to watch because there are no other levels. With Sesame Street, what we constantly try to do is try to do a parody -- 'Mad Men,' '30 Rock' -- so the parent will get one part of the joke and the kid will get the other part."
To critics who say kids shouldn't watch TV, Truglio says there's more going on when kids watch "Sesame Street" than meets the eye.
"For children there is a lot going on -- cognitively they are engaged, just because they're not mimicking what they're seeing, we know that they're learning. Very similar to reading a book … you're engaged, reading, taking it all in," said Truglio. "TV is a tool that we use to educate. There's lots of good on TV, and lots of bad. But the role of 'Sesame Street' as an educator is proven. I think we encourage kids to go out and play -- after the show's over of course."