Sesame Street by Richard Termine/PBS Sesame Street by Richard Termine/PBS

"There's a lot of new stuff in store," promises executive producer Carol-Lynn Parente when talking about the 39th season of Sesame Street (Mondays, 9 am/ET, PBS, time may vary in your area), the gold standard in preschool programming.

This year, the goal is to make math fun with such parodies as "Preschool Musical," "Are You Smarter Than an Egg Layer" and "30 Rocks." In the season opener, Feist sings her catchy "1234" with new lyrics ("1234, chickens just back from the shore...") and Jack Black pals around with Elmo.

More A-list stars will show up later in the season, including Jessica Alba, David Beckham, Heidi Klum, Neil Patrick Harris, Randy Jackson, Sandra Oh, Jenny McCarthy and newsman Brian Williams, who shows his sense of humor while reporting on a case of "mine-itis." But Sesame Street purists should be warned: Two beloved Muppets have a different look as the series introduces Claymation versions of Bert and Ernie. At least Super Grover remains untouched! - Megan Walsh-Boyle