Groucho Marx's idea when he was banned from a pool because he was half-Jewish.Upon being denied, in the 1950's, membership in the exclusive Hollywood Country Club, because he was a Jew, Groucho Marx (whose father was a Jew, but whose mother was not) wrote a letter to the club's membership asking to be admitted.

"Being only half Jewish, I promise to get into the swimming pool only up to my waist."