On Nov. 10, 2009, Sesame Street celebrated its 40th anniversary, making it the longest-running children's show on U.S. television. Multiple generations of wide-eyed kids have fallen in love with the entertaining, educational and inspiring residents of the friendliest street in town, and this season promises even more laughs and life lessons. And giving the show the presidential seal of approval? First Lady Michelle Obama, who opened the40th season as the first celebrity guest. Season 41 begins on Sept. 27.