In December of 1964, the Muppets were booked for a guest spot on The Jack Paar Program, a prime-time Friday night talk-variety hour. The Muppet team -- Jim Henson, Frank Oz, Don Sahlin and Jerry Juhl -- arrived at NBC Studios in Radio City for a 10am rehearsal, but they were informed that they weren't actually needed on stage until 4pm. With lots of time to kill, they opened a door in their dressing room and found that it was filled with dark, dusty pipes. Juhl remembers, in a 1992 interview: As the day went on, Juhl recalls,