Two come to mind (and I’m paraphrasing):
Clue: The Romans rode on these 2-wheeled vehicles when attacking their enemies.
Response: What are bicycles?
Clue: The male attendants at a wedding.
Response: What are pallbearers?
IIRC, both of these were in the same game, possibly from the same contestant.
Alex Trebek should write a book of these, plus out-takes.
A young woman years ago in Final Jeopardy:
Answer: The name of the first Space Shuttle Orbiter.
Her question: What was the Enterprise?
The woman then flipped out when informed she was correct. (paraphrased) “NO! I put it as a joke. I didn’t know the answer.”
I truly recall:
Category: Road Signs
Answer: The primary color associated with “Stop” and “Yield”
Question: What is purple?
IIRC, it was dubbed the Enterprise at then-president Gerald Ford’s insistence, because he was a Star Trek fan.
It was Celebrity Jeopardy, so it’s non-canon, but there was an actor (I can’t remember his name, he’s black, bald, and plays authority figures) who had trouble with the “form of a question” part of the game.
His responses were consistently along the lines of “Water… what’s that?”.
Watching him retcon his responses was priceless.
During the “Getting to know the players…” Alex asked a woman about her wedding. She wanted to get married in the snow. He asked if she got any and She said something along the lines of: On my wedding day I got 7 inches.
The time the guy who didn’t know answered (appropriately) with Cliff’s famous line “Who are three people who’ve never been in my kitchen?”
No, they didn’t give him the money either.
For fans of “The Honeymooners,” this will need no explanation (for those who aren’t… no explanation would help explain why this was hilarious!).
There was an episode years ago in which a guy rang in, knowing the answer… then completely drew a blank! As time was running out, and he realized he wasn’t going to be able to remember the answer he had on the tip of his tongue just moments before, he said, “Uhh… who is Ed Norton?”
My choice is a non answer. The category was “Starts with M” (you have to read the spoilers to understand):
100 In “South Pacific,” they sing that this bananas and this fruit can be “picked right off a tree.”
What is mango?
200 In “Flash Gordon,” Ming was ruler of this planet.
What is Mongo?
300 Daniel Boone’s Indian sidekick on the TV show, played by Ed Ames.
Who was Mingo?
Now, the $400 question was revealed to be an audio daily double.
Given the following, you should be able to guess the correct question.
The contestant couldn’t even get it when the song was played.
Who is Mungo Jerry? – the song was, of course, “In the Summertime”
I’ve seen at least two people use the “not in my kitchen” response based on a Cheers episode.