Or you could have this conversation, like I do:
“Knock, knock!”
Me: “Come in!”
(pause) No, you are supposed to say: “Who’s there?”
Me: “But I can see you. I already know who is there.”
“Um. It’s a joke. Haven’t you ever heard a KnockKnock joke?”
Me: “No. Tell me one.”
Okay. “Knock, knock!”
Me: “Come in!”
Not a knock knock joke but my go to joke…Why did the elephant paint his toenails red? So he could hide in a cherry tree. Have you ever seen an elephant in a cherry tree?? See? It works!?
Have i ever mentioned that I work in an elementary school?!
@mc2d2000 oh my gosh…I thought I was the only one who told that joke, lol! My sister taught it to me when I was a kid and I always thought it was funny. (and as a former elementary teacher, I definitely pulled it out with my students! )
My favorite knock knock joke that I have used many times (and has generally gotten a chuckle):
Me: hey! I’ve got a great knock knock joke for ya! You start!
Them: ok. knock knock
Me: who’s there?
Them: confused silence
In all fairness…it’s probably funnier to me than it is to them. I love the look on their face when they realize they’re on the spot for the joke and it didn’t go quite like they thought it would. I usually get “that’s different”
Or you could have this conversation, like I do:
“Knock, knock!”
Me: “Come in!”
(pause) No, you are supposed to say: “Who’s there?”
Me: “But I can see you. I already know who is there.”
“Um. It’s a joke. Haven’t you ever heard a KnockKnock joke?”
Me: “No. Tell me one.”
Okay. “Knock, knock!”
Me: “Come in!”
@rockblossom Similar to my reaction.
“Knock, knock”
Me: What?
First person who blinks, loses.
Reminds me of this:
Why did the chicken cross the road?
To visit the idiot…
Knock knock
==>Who’s there?
The chicken
Then there is my favorite joke EVER:
Baby seal walks into a club…(ɪɴsᴇʀᴛ ʀɪᴍsʜᴏᴛ ᴀɴᴅ ʜʏsᴛᴇʀɪᴄᴀʟ ʟᴀᴜɢʜᴛᴇʀ)
Not a knock knock joke but my go to joke…Why did the elephant paint his toenails red? So he could hide in a cherry tree. Have you ever seen an elephant in a cherry tree?? See? It works!?
Have i ever mentioned that I work in an elementary school?!
@mc2d2000 oh my gosh…I thought I was the only one who told that joke, lol! My sister taught it to me when I was a kid and I always thought it was funny.
(and as a former elementary teacher, I definitely pulled it out with my students! 
)
@mc2d2000 How did Tarzan die? (Answer) Picking cherries!
@k4evryng @mc2d2000 we used to say “strawberry patch” because cherries don’t grow in South Florida.
@bmf Bwahahahahaha!
@doubltap Knock, knock
Who’s there?
We’ve been trying to reach you about your car’s extended warranty.
Why did the chicken cross the road?
@mike808 To prove to the armadillo that it could be done.
@rockblossom @werehatrack
Nope.
To get to the idiot’s house.
@rockblossom @werehatrack
Knock, Knock.
@mike808 Why did the man cross the road?
Because he had his dick stuck in a chicken.
@rockblossom @werehatrack @llangley @detailer
Knock Knock.
@mike808
(opens door) Hi, neighbor! Thanks for bringing back the chicken. I don’t know why she keeps going to your house.
My favorite knock knock joke that I have used many times (and has generally gotten a chuckle):
Me: hey! I’ve got a great knock knock joke for ya! You start!
Them: ok. knock knock
Me: who’s there?
Them: confused silence
In all fairness…it’s probably funnier to me than it is to them.
I love the look on their face when they realize they’re on the spot for the joke and it didn’t go quite like they thought it would. I usually get “that’s different” 
@k4evryng I like to flip that gotcha back at them with “Banana”. See below.
I recently bought a shirt with my favorite annoying knock-knock joke on it. I thought I was the only one who remembered it.
Knock knock
Who’s there?
Banana
Banana who?
Knock knock
Who’s there?
Banana
Banana who?
Knock knock
Who’s there?
Banana
Banana who?
Knock knock
Who’s there?
Orange
Orange who?
Orange you glad I didn’t say banana?
OK, how do I put the picture in the post? Is that not possible on my phone?
@lisagd
I’m sure if you concentrate hard enough, anything is possible.
@lisagd @mike808 Or your efforts could be fruitless.
@lisagd turn your phone sideways & click on the mountain symbol.
@lisagd
The version I heard responded to “Banana who?” with “Banana banana. Knock knock.”
@lisagd
@lisagd
@werehatrack The blue one is the one! Thanks!