The Muppets Valentine show was the first of two pilots for The Muppet Show. Valentine aired on ABC in 1974. Though the second pilot, The Muppet Show: Sex and Violence would be a closer prototype of the series, Valentine laid the groundwork with some characters, the idea of having a guest star, appealing to both adults and children, and the format of putting on a show with "behind the scenes" mayhem. (thetvdb.com)