Sunny Day (Sesame Street)
Sesame Street was the first TV show to merge entertainment and learning for the preschool set and is largely responsible for children starting kindergarten knowing their letters, numbers, and colors. The show, which airs in more than 120 countries, has won more than 100 Emmy Awards, making it the most award-winning TV series of all time. The cheerful and idyllic theme song was written by Joe Raposo, Jon Stone, and Bruce Hart, but the singers are all children. Or at least they were when the show debuted in 1969!