When I was a kid, there was an afternoon children's show on the week-ends called Buster Brown. And there was a frog puppet who helped introduce the (obligatory) cartoon during the show. He did this by pulling down on a flexible pole that when released gave a boiiiinngg sound -- like a Jew's harp.

Buster Brown (another puppet) gave the invitation to pull the lever down, do the boiinngg sound and start the cartoon by saying, "Plunk your magic twanger, froggie!!" My father about died when he heard that one afternoon. I didn't know what the big deal was.

Nowadays, whenever @catweasel and I publish The Daily Whistle Stops ---> when everything is ready to go, our signal to publish is "Plunk your magic twanger, froggie." Some things never die. (Oh, Lord!)

See: Buster Brown