Harpo Marx tells the story about how his "Gookie" face came to be.
Over the years, in every comedy act or movie I ever worked in, I've "thrown a Gookie" at least once. It wasn't always planned, especially in our early vaudeville days. If we felt the audience slipping away, fidgeting and scraping their feet through our jokes, Groucho or Chico would whisper in panic, "Ssssssssssst! Throw me a Gookie!" The fact that it seldom failed to get a laugh is quite a tribute to the original possessor of the face.
(thx, mark)