The TV version of Sesame Street often ropes in a famous actor, politician or musician to do a little sketch with the adorable muppets. The show has played host to such figures as Johnny Cash, Richard Prior, Oprah Winfrey, Hillary Clinton and Julia Roberts. But, since this is YouTube, producers have sought out partnerships with figures who have become stars from shows on the video-sharing service. So, Elmo will appear in clips with Simon's Cat, Eh Bee and Jerome Jarre, while Cookie Monster gets a lesson in food preparation from Rosanna "Nerdy Nummies" Pansino.

Sesame Street is something of a towering institution that, you feel, is a permanent fixture of our culture. But the truth is very different, with Sesame Workshop (formerly known as the Children's Television Workshop) suffering from a funding crisis. In 2009, the nonprofit felt the bite of funding cuts, and began operating at a significant loss, which was only exasperated by the decline in physical media sales, which had previously been covering the shortfall. These days, HBO has stepped in to help, which has given the Workshop time and space to develop new projects online as well as launching its own startup incubator.