On this day in 1969, transcendent children's program Sesame Street debuted on PBS, changing television forever. After the jump, a collection of some of the Street's most memorable guest appearances, complete with our favorite: kids freaking out to Stevie Wonder's "Superstition."

CONTINUED »

SESAME STREET FIGHTS TO STAY COMPETITIVE "Nearly 40 years ago 'Sesame Street' forged a new path in educational television for preschoolers. But in recent years, as even very young children have migrated online, the show’s Web efforts have lagged far behind those of commercial competitors like the Walt Disney Company and Viacom’s Nickelodeon. The show’s nonprofit parent, Sesame Workshop, hopes to change that on Aug. 11, when the new Web site sesamestreet.org goes live. Developed over two years at a cost of $14 million, the site is making its debut the same day as Season 39 of 'Sesame Street,' seen weekdays on PBS."