- The Noodle Incident (as in, the Noodle Incident) never gets explained, though whenever someone mentions it, Calvin becomes panicked and defensive. Watterson stated that he originally intended to explain it, but realized he couldn't make up anything that would be as funny as what the readers would invent trying to figure it out.
- Calvin's favorite bedtime story, Hamster Huey and the Gooey Kablooie. Similarly to the Noodle Incident, Watterson is on record as saying that he will never define what the story is actually like, because inevitably it would be funnier in the reader's head. There's also the sequel, Commander Coriander Salamander and 'Er Singlehander Bellylander, which is mentioned in only a single strip and which Dad has an even lower opinion of. Funnily enough, there now is a children's book named after the first fictional book, by one "Mable Barr" (the in-universe writer was "Mable Syrup").
- The only hints revealed of what was in the book is that there is a dance called the "Happy Hamster Hop", and that reading it aloud requires "squeaky voices and gooshy sound effects".Mom: But you look so cute doing the Happy Hamster Hop.
Dad: I don't WANT to look cute!
- Once, Calvin's dad got irritated with the actual story and began to ad-lib; we didn't hear that story either, but Calvin and Hobbes are visibly terrified afterwards and Hobbes wondered at the end whether the townspeople ever found Hamster Huey's head.
- The only hints revealed of what was in the book is that there is a dance called the "Happy Hamster Hop", and that reading it aloud requires "squeaky voices and gooshy sound effects".
- In one strip, Calvin complains to Hobbes about how much trouble he got into that day in school, but when Hobbes asked what happened, Calvin says he doesn't even want to talk about. When Hobbes asks if it had "anything to do with those sirens [he heard] around noon", Calvin repeats, louder this time, "I SAID I don't want to talk about it."
- In the strip that immediately preceded this one, Calvin is getting dressed for school, complaining about how it never changes, and then says, "Well, not today. Today, I go for the gusto." and puts on a cape and space helmet, which seems to suggest the obvious. Moderate consensus among fans is that this is indeed the specific date/strip that the Noodle Incident occurred, as no other school exploit of his ever got all the way up to the level of emergency sirens.
- Calvin tells Dad it's amazing how many things you can take apart with just an ordinary screwdriver. Dad says "Such as?" Calvin realizes he's said too much and stammers that he doesn't really know and was just speaking hypothetically. Then he walks away, telling himself that he needs to stop introducing topics of conversation. How many things did Calvin take apart with a screwdriver, and what were they?
- In one strip, Calvin tells his dad that it's possible to buy live squid at the supermarket. His dad half-registers this... then realizes what's going on and screams "CALVIN, WHAT ARE YOU DOING?"
- Calvin's show and tell from this strip... if he even had a show and tell.Calvin: Today for "show and tell", I refuse to show you what I brought and I refuse to tell you anything about it! It's a mystery that will haunt you all your miserable lives! You'll never, ever know what I brought! You can beg and plead, but I'll never end your torment! I'll carry my secret to the grave! It's the show and tell that was never shown or told! Ha ha ha! Ah ha ha ha ha!
(Cut to Calvin walking to the principal's office)
Calvin: Everybody wants the same old thing.
- In one strip, Calvin and his mom come back from a children's matinee movie. He had barely noticed there was a movie on, and she looks messy and extremely tired (and demands they purchase a video player when asked how it went by her husband). Obviously he found something else to do.
- In one strip, Calvin asks Hobbes a "hypothetical" question about whether he should tell Dad if he's done something bad. Involving his car. Which could perhaps be repaired if it could be found first...note Calvin: Hey Dad, remember our car?
Dad: Why sure... Wait a minute, what do you mean "remember"?
- Calvin once called his dad and asked him to pick up topsoil and grass seed on his way home from work. Dad, being busy, brushes it off with "OK, sure. Goodbye." We then see Calvin walking away from the phone covered in dirt and carrying a big shovel and pickaxe, and Calvin's dad looking very puzzled.
- Another strip has Calvin asks his dad "Would you still love me if I did something bad?" He means something "really, really" bad. Dad yells "CALVIN, WHAT DID YOU DO?!?"
- Calvin's parents are once shown discussing child rearing after "the contractor says it will cost $200 to fix". It's never mentioned what exactly Calvin broke.
- One strip shows that Calvin flooded the house. How he did this is never touched upon. As with the crashed car incident, there was a later Story Arc that showed just how a milder version of the same thing happened another time.
- Another strip, he's worried about his dad finding out he broke his dad's binoculars. When Hobbes suggests that maybe Calvin could repair the binoculars, Calvin goes and gets the binoculars. He brings a box and tells him "don't sneeze" as he pours out a pile of very tiny pieces. While it was mentioned in the previous comic that he was tossing the binoculars in the air while running down the sidewalk, how it went from that to a pile of dust is not explained. This could be more about comedic exaggeration than implying an actual incident.
- The throwaway gag in this strip◊, we never find out what Calvin said about his dad by writing in the snow. Similarly in this strip, Calvin's dad doesn't even want to know what he planned to write when he said he wanted to write messages in gasoline and light them on fire at night so airline pilots can read them from overhead.
- Many strips involving C&H's infamous sled and wagon rides are left mostly to the readers' imaginations. For example, in one strip the sled apparently caught fire before they crashed it into a pond, while in another, the wagon somehow launched itself and them into the boughs of a tree so tall they could see for miles.
- The first strip of the Uncle Max story arc had this exchange about why they haven't seen him in a while.Calvin: Why not? Was he in jail?
Mom: No! Good Heavens, Calvin!
Dad: Now now, with Max, that's actually not a bad guess.
- One Christmas strip has Calvin's furious mother throwing him out of the house for singing a novelty Christmas song too many times. We never find out what novelty Christmas song exactly it was.
- One story arc had Calvin's parents taking him to the zoo. While at the monkey house, Calvin notes that one of the monkeys is doing something gross in public and asks why he isn't allowed to do that. What the monkey is doing is never shown or described; Calvin's parents just try to redirect his attention to some birds.
- After a week-long camping trip suffused by rain from beginning to end, only for the sun to appear immediately after everything was packed up, the final panel implied that Calvin's dad let out a Cluster F-Bomb in frustration. We never learn what he said, or if it was a simply a case of Angrish similar to the father's reaction when he drops something heavy on his foot.Calvin: (eagerly) Do you know what any of Dad's words meant?
Hobbes: No, but I wrote some of them down so we can look 'em up when we get home.
Nothing Is Funnier / Calvin and Hobbes