After more than 50 years, "Sesame Street" still has something to teach us --- at least those of use plopped in front of it as pre-schoolers who never had a sense of how it came to be.
The author Michael Davis presented that history in the 2008 book "Street Gang: The Complete History of 'Sesame Street,'" and now the director Marilyn Agrelo ("Mad Hot Ballroom") has made a documentary version, which takes full advantage of clips, outtakes and interviews, recent and archival.