Two porcupine parents are sitting on the couch. Baby sits on the floor, playing happily with a balloon.
“Well, this won’t last long.”
Demons in hell, cracking up as they read the slips in the suggestion box.
Two bugs looking out their living room window at the guests coming up the sidewalk. “It’s the dung beetles…and they brought it with them.”
My husband has this one up over his desk at work.
We often use “cumulative attack of the willies.” 
A dog leaning out the window of a car parked in the driveway, telling another dog.“First we’re going to the store, then I’m going to the Vet to get tutored!”
“Notice, gentlemen, that the faster I go, the more Simmons sounds like a motor boat.”
Two spiders, pile of web beneath one, other one saying “Hey Bob did I scare you?”
A group of gold fish are standing outside of the goldfish bowl watching their plastic castle go up in flames.
Caption: “Well, thank God we all made it out in time… 'Course, now we’re equally screwed.”
A medieval castle under siege, with a soldier being carried down from the tower with an arrow in his butt. Caption: “And so I said to him, as long as we’re besieged up here, Brog, one of us ought to moon those Saxon dogs!”
Interior of a farmhouse. Caption: “The cows got into Farmer Brown’s house, and were having the time of their lives until Bessie’s unwitting discovery.” Bessie is standing in front of the freezer, with the door open. The expression on her face is priceless.
First panel: Cows in a field, standing around conversing
Cow apparently on lookout duty yells, “Car!”.
Second panel: Car drives past cows calmly grazing in the field.
Final panel: Cows standing around conversing.
View from behind a man in a stovepipe hat standing at a lectern. The sheet of paper in front of him reads “… so the bartender says ‘Hey, wait! That’s not a duck!’ (wait for applause) Four score and seven years ago…”
Detectives in a laboratory setting with dead cats slumped over microscopes and other lab equipment with one saying “No doubt about Norm - curiosity killed these cats”.
Medieval castle with two guys next to a catapult and another one flying through the air in distance - their leader saying “I told you guys if you didn’t slow down something like this would happen” (I like this because surely sometime in history something like this actually happened).
Two cavemen standing next to a big hole with a huge partially knawed peice of meet hanging above it. One is jumping up and down shouting “We got the big one! We got the big one!” ; the other cavemen teetering and about to fall in from the first’s leaping celebration. The OMG look on the one about to fall in is classic Larsen.
Heh, I don’t remember that one. The one I do remember is two chickens sitting in a bar (you know the ones, with the cat’s eye glasses), and the rest of the patrons are cows. The caption (IIRC): To her horror, Edna realized she was in a hay bar.
“Boneless Chicken Ranch.”
A living room scene with a mother ant and several ant children. The father ant is walking in the front door, wearing huge shoes and squishing several of the children. Mother ant says “Ernie! Look what you’re doing - take those shoes off!”
Two hunters are in African savannah grass. Several cape buffalos stand, along with a mime, looking apprehensively at the hunters. The hunter in front hands his rifle to the hunter in the back: “Situation’s changed Jules … Take my buffalo gun and hand me my mime rifle.”
A kangaroo with a cast on his foot is holding a pogo stick and talking to another Kangaroo.
He’s saying something along the lines of “I should be done with this thing in another few weeks”.
Dog hanging out a car window talking to another dog who’s sitting in a yard, bragging about how he’s “Going to go get TUTERED!”
A couple of praying mantisy looking “housewives” in the living room. One is offering a tray of goodies to the other who says “My heavens no Gladys, I couldn’t. I just ate my young an hour ago.”
This is still a catchphrase between my brother and me.
Going from memory here: Large building, labeled something like “Thompson’s Haywire Corporation,” has smoke coming out of some windows and wire out of others and panicking people visible inside. At one window is a lady on the phone, saying something like, “Mr. Thompson, first number seven came off the spool, then they couldn’t get [something else] to work, and then it all pretty much went You-Know-What.”
An occupied outhouse in the foreground, with a word balloon coming from inside. “Dangit! Again?” In the distance, a Saint Bernard with a roll of toilet paper hung around his neck instead of a barrel of brandy cocks his ear. Caption: “Far away, a very special breed of dog heard the cry.”
My all-time favorite: Still-smoking time machine at the top of a hill. Dinosaur rear end visible in foregroud. Striding purposefully toward said dino butt is an utterly fearless white-coated scientist carrying a pole-sized rectal thermometer over his shoulder. Caption: “Moments later, Professor So-and-so’s experiment ended in disaster, forever clouding the question, cold-blooded or warm-blooded?”
All time favorite:
“Unwittingly, Palmer stepped out of the jungle and into headhunter folklore forever.”
Palmer has about a 55 gallon head.
God is up in the clouds standing in front of a table rolling out what looks like play-doh into a play-doh snake on the table.
God says, “Dang these things are easy”.
Caption at the bottom. “God makes snakes.”
Two hunters are looking at an elephant and the one says, “Careful. This one has a knife.” The elephant, ideed, has a switchblade.
It really is amazing how many people have a favorite one, and they’re all hilarious.
Here’s mine: at a cocktail party, a wolf is holding a sheep by its back legs over a bowl and says to a fellow wolf cocktail-party-goer, “Well, I’m addicted. Have you tried Carol’s sheep dip?”