Fred Sanford:
“Lamont, you big dummy!”
“Esther, you’re so ugly.”
“How’d you like one across your lip?”
“IT’S THE BIG ONE! You hear that, Elizabeth? I’m comin’ to join you, Honey.”
Hogan’s Heroes:
“I know nothing!”
“What is this man doing here?!” (Always said three times, in increasing volume and exasperation)
“Dental plan”
“Lisa needs braces”
“Dental plan”
“Lisa needs braces”
“Dental plan”
“Lisa needs braces”
“Dental plan”
“Lisa needs braces”
“30 days in the cooler.”
Colonel Klilnk: “Hogan.” So popular the Simpsons had him saying “Homer” the same way.
Another Sheldon Cooper one: I’m not crazy. My mother had me tested.
Knock knock.
Who’s there?
Banana.
Knock knock.
Who’s there?
Banana.
Knock knock.
Who’s there?
Banana.
Knock knock.
Who’s there?
Banana.
Knock knock.
Who’s there?
Orange.
Orange who?
Orange ya glad I didn’t say “Banana”?
“Simpson, eh?”
Then there’s this knock knock joke:
Knock knock
Who’s there?
Knock knock
Who’s there?
Knock knock
Who’s there?
Knock knock
Who’s there?
Knock KNOCK
Who’s there?
Knock KNOCK
Who’s there?
Knock KNOCK
Who’s there?
Knock KNOCK
Who’s there?
Knock KNOCK
Who’s there?
KNOCK knock
Who’s there?
KNOCK knock
Who’s there?
KNOCK knock
Who’s there?
KNOCK knock
Who’s there?
Phillip Glass
It goes back (at least) to radio. The Goon Show was full of catchphrases, every character had at least one or two that showed up in every script, and a few others that were used more sparingly. Some were just nonsense, like “Needle, noddle, noo” and “Ying tong iddle hi po.” While waiting for applause or a laugh, “not a sausage.” The humor of these kinds of phrases is pretty much completely reliant on using them at the right time in the show.
“Know the truth and the truth shall SET YOU FREE!”
“I know the truth, and the truth is, you ugly!”
“Is there a Homer Sexual here? Come on, one of you guys has gotta be Homer Sexual.”"
“Amanda Hugginkiss? I need Amada Hugginkiss!”
"Mike Crotch? Has anybody seen Mike Crotch lately?
“Hugh Jass! Can somebody check the men’s room for a Hugh Jass?!”
“Bea O’Problem? Bea O’Problem! Come on, guys, do I have a Bea O’Problem here?!”
“Anita Bath? Anita Bath here? All right, fine, fine. Maya Buttreeks.”
Just thought of one from Bonnie and Clyde, which I will only say involves a joke where choosing not to get rid of a certain piece of livestock is the punchline, a joke told by Clyde’s brother Buck.
FULL spoiler:
“Whatever you do, don’t sell that cow!”
In the first telling of the joke, the humor comes from its actual “funniness”. As the gang’s situation becomes more and more dire, Buck hauls the joke out again and again in order to inject some general lightheartedness into the air. The people who are hearing for the first time find it uproarious, while the others, who are being subjected to it for the umpteenth time, find it grating, given the shit that they increasingly have to suffer through as the law closes in.
I was just thinking, a running gag that is itself a running gag I win the thread! 
I just thought of Green Acres before seeing your post. Great stuff! I always heard the above one as, “Oh, for the love of…”, where Oliver would always trail off because the censors wouldn’t have let him get away with saying “…for the love of God.” 
But this reminds me, I’ve go to go back and check out this show again. Growing up, while I got the jokes, I never fully appreciated the existential? nature of a lot of Green Acres as a kid. For instance, remember what they would often do for the opening credidts? I don’t, and it’s one of the many reasons I want to go back and see this again.
…in ‘The Wire’: “Happy now, bitch?”
Isn’t pretty much 90% of Family Guy cutaways this?
Did the big chicken tell you to post that?
Krause from Benson: I Hear You
“Put it in a sock, Benson!”
The shark scene in Strange Wilderness
The repetition is as funny as anything else. Wouldn't be as funny as a one-off."There you go again, Jimmy…giving a fuck when it ain’t your turn to give a fuck.’
And Omar: “Oh, indeed.”
In most of the Road Runner cartoons, Wile E. Coyote usually gives up his latest scheme after it fails. Even when it was due to either bad luck, his own mistakes, or an unanticipated failure mode, when conceivably it might have worked if he’d tried again. One of the few times he tried repeatedly was with the boulder-tossing catapult.
He first tried it standing behind it; the boulder fell off the bucket on him.
He tried standing further back; the entire catapult flipped back onto him.
He tried standing in front of it; the catapult only tossed the boulder far enough to land on him.
He tried standing to the side of it;the boulder was tossed sideways onto him.
He tried hiding under it; the catapult collapsed on him.
He tried hiding inside a covered manhole; when there was no way it could possibly reach him, then it simply refused to work. Until he made the mistake of coming out and trying to unjam it.