Here's a clip from the episode of You Bet Your Life that aired on May 11, 1961. The autobiography of Harpo Marx had just been published and he made a cameo appearance on his brother's show to promote it. Note that Groucho looks often at his off-screen prompter. Many of what seemed to be ad-libs were read off a screen not unlike the kind then used in bowling alleys to post scores. Harpo and Chico had both appeared on the show before, not in the studio but in a series of commercials for one of its sponsors, Prom. Come to think of it, I'll post that one, too…
