Jack Benny: And now a word from our sponsor. Take it, Don. Don Wilson, the show's MC: "Jell-o." Take it, Jack.
Adventures in Odyssey has been around for over twenty years, and it knows it. Just to name one example, the narrator, Chris, ends every episode by giving the show's address and listing the main credits for the episode. The inevitable pokes at this have gone from prefacing it with a "(Ready?)" in "Switch", to having the show's production team hijack it over her protests in "500", which was topped in "Live at the 25" when she led the entire audience in reciting it.
Cabin Pressure, a BBC radio sitcom about a very small airline, featured Benedict Cumberbatch as one of the pilots, except for the first episode in Series Three when he was unavailable and the part was taken by another actor. This was lampshaded by the other characters discussing what they would do if one of the pilots was ill and deciding that they would think of something. The replacement actor entered at this point and the flight attendant complimented him on how well he was looking; only for the co-pilot to reply: "No, I think he looks exactly the same as always!"