The phrase "Who is on" is most famously associated with the classic comedy routine "Who's on First?" by Abbott and Costello. This sketch revolves around a humorous misunderstanding about the names of baseball players, where "Who" is actually the name of the first baseman, leading to confusion when asking "Who is on first?" The routine is a well-known example of wordplay and has been performed hundreds of times since its debut in 1938. It remains a significant part of American comedy history, even being honored with a gold record in the Baseball Hall of Fame and recognized by the American Film Institute as one of the best comedy sketches of the 20th century
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