Probably the best of the Letterman videos. "Dancing in the Dark." This an ancient file and the quality is poor. As pointed out in the comments, Joan Rivers was the narrator, and Gene Wilder voiced The Letterman.
The Electric Company aims to entertain children between the ages of 6 and 9 while teaching four crucial areas of literacy that are challenging for struggling readers: decoding, vocabulary, comprehension of connected text, and motivation.