When the writers openly acknowledge that a Running Gag has run its due course, even as they are hauling it out again— gain— gain— gain— *WHACK* There we go. Anyhow, the use of a Running Gag is generally constrained over the course of one episode. But there are some jokes that the writers thought are just so funny that they should be used in another episode, and another, and another and another. Even if it isn't Once an Episode, it's still squeezed into the series wherever they see fit— fit— fit— fit— fit— *THUMP* Compare Discredited Meme, which this often leads to— to— to— to— to— *WHUMP*