My guess is to keep the adults engaged. If an episode of Sesame Street has a cameo from a known actor or musical star, that's for the adults, not really the ki

My guess is to keep the adults engaged. If an episode of Sesame Street has a cameo from a known actor or musical star, that's for the adults, not really the kids. (The Katy Perry/Elmo Stop and Go song is really catchy, for example.)