I posted this back in 2014 but that link no longer works, we have a better copy available and today (for the next three minutes) is the anniversary of its first airing.
It's "The Incredible Jewel Robbery," an episode of General Electric Theatre that was seen on March 8, 1959. It stars Harpo Marx and Chico Marx and since one of their brothers — no, not Zeppo — appears in a surprise cameo at the end, it's the last appearance of the Harpo, Chico and You-Know-Who together on a screen. The story is silent until You-Know-Who gets the last line…