What's My Line?
From Zappa Wiki Jawaka
"What's My Line?" was an American game show (1950-1975) on CBS, where the contestants are blindfolded and have to guess the identity or profession of a celebrity by asking him questions and listening to his answers.
Frank Zappa was a guest on this show on September 23, 1971. Panel member Soupy Sales was able to guess Zappa's identity.