Lots of jokes and gags, whether they’re just a single word or a phrase, get repeated as a form of “running gag” of sorts, or just as an isolated piece of stupidity.
This can be in film, tv or music.
The first that immediately comes to mind has to be Monty Python’s “spam, spam, spam…” and the only other one I can currently think of is in Taxi, where Christopher Lloyd is trying to write a driving exam and keeps on asking “What does a yellow light mean?” as soon as he’s told “Slow down”.
Also, Python’s “It’s the Mind” sketch where the beginning is constantly repeated as Micheal Palin introduces with “Good evening. Tonight on ‘It’s the Mind’, we examine the phenomenon of deja vu”.
And two from Holy Grail:
“Bring out ch’a dead”
The chanting line of monks sing a latin phrase and then bonk themselves on the head with a piece of wood, over and over.
One I like was from near the end of the video game Portal 2:
GLaDOS: Well, this is it. This is the part where he kills us.
Wheatley: This is it! The part where I kill you.
CHAPTER 9: The part where he kills you.
Achievement: The part where he kills you (this is that part).
Sideshow Bob and the rakes.
“No. No. No. No. No. No.”
Monty Python’s ‘Cheese Shop’
“Her?”
From Arrested Development. It’s not even a joke…they just kept having people say, “Her?” when talking about someone and it became a joke through repetition.
[in unison, though only one knows why he’s saying it]
“THIRD BASE!”
A somewhat unhinged Leahy going on a propane, propane, um, thing.
Obscure because most haven’t seen the play, but * Peter and the Starcatcer* takes the sentence “Oh, my God” and makes it hilarious by repeating it.
From Vaudeville:. “Niagara Falls! Slowly I turned…”
“Oh my God, they killed Kenny!”
“It’s rabbit season!”
“Duck season!”
“Rabbit season!”
“Rabbit season!”
“Well, I say it’s duck season. FIRE!”
“We were on a break!”
“Put the candlestick back.”
“What hump?”
“I just want to tell you both: good luck. We’re all counting on you.”
“I’m Larry. This is my brother Darryl and this is my other brother Darryl.”
“Pitter patter, let’s get at 'er.”
“I’ve heard it both ways.”