An aspiring TV anchorman is conducting a "man in the street" interview program as part of his way up the ladder. The topic of the day was knock-knock jokes.
"Yessir, do you have a knock-knock joke?"
The inebriated, kinda mangy guy replies. "Yesh I do! Knock-knock!"
"Who's there?"
"Argo!"
"Argo who?" the reporter obligingly asks.
"Argo f--k yourself!" is the punch line and the drunk wanders off with considerable self-satisfaction.
The station goes nuts, shuts down the program, fires the anchor as word spreads throughout the industry. The poor fellow is crushed.
However, he decides to try again. He gets jobs as a volunteer at small stations in Eash Armpit, Nebraska, moving up to Bumscrew, Arkansas, and on up. Finally, after eight years he's again conducting an interview program, punching his ticket. He's also spent thousands of hours tracing down every knock-knock joke the world has ever known.
After a while a very respectable man, suit, tie, comes up to him, waits his turn, and says to the fellow, "Knock-knock." With a good measure of trepidation he replies, "Who's there?"
"Walnut."
Guy thinks. Can't do much damage to ask. "Walnut who?"
The interviewee pauses a second, and says "Argo f--k yourself!"

I don't know what that has to do with anything, but it might.