Topic summary
Running gags

Extracted from the Wikipedia article Running gag.
Running gags can begin with an instance of unintentional humor or a one-time joke that provokes a strong response, and is repeated in variations as the joke grows familiar and audiences anticipate reappearances of the gag. The humor in a running gag may derive entirely from how often it is repeated, but the underlying statement or situation will always be some form of joke. A trivial statement will not become a running gag simply by being repeated. A running gag may also derive its humor from the (in)appropriateness of the situation in which it occurs, or by setting up the audience to expect another occurrence of the joke and then substituting something else (bait and switch). Running gags are found in everyday life, live theater, live comedy, television shows, video games, films, books, comic strips, and potentially any other situation in which humor is possible and there is enough time for the repetitions to happen.