- In one strip, Calvin's mom is watching TV and Calvin is complaining about all the kissing the characters are doing. His mom announces "bed time" and carries him up to his room. The last panel has a bewildered Calvin remarking, "There's a connection here, I just know it."
- One strip had Calvin ask his mother why it was "worth four dollars a minute to talk on the telephone to goofy ladies who wear their underwear on TV commercials".
- He also asked his dad why "he lives in this house with Mom instead of an apartment with several scantily-clad female roommates." Quite explicably, this leads to him getting all of his television privileges revoked.
- Then there's the one program we get to overhear him watching, which doesn't so much get past the radar as utterly destroy it (note that the following is punctuated by kissing noises):
"Oh Mary, you look ravishing in that skimpy negligee!Mmm…darling, don't you wish we were married?""But we are! …Or did you mean to each other?""I've got to have you! Let's murder our spouses!""Murder?!—You sick animal! I love it when you talk that way! Come here!"Calvin, smiling widely: Sometimes I think I learn more when I stay home from school.
- A number of early strips see Calvin trying to get into or rent R-rated movies with pretty suggestive titles, like "Venusian Vampire Vixens," "Attack of the Co-Ed Cannibals," or "Cannibal Stewardess Vixens Unchained."
- In one strip, Calvin's gum-chewing leads to the memorable line from Hobbes: "An orifice is an amusing thing, all right."
- At the end of one strip, Calvin's dad receives a call from his wife at work to which he answers: "Look, Honey, could we talk about that operation some other time?" What's the context? Well, Calvin had just been asking his mom for a baby brother, but only so he could have someone smaller to bully.
- 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 combined a Noodle Incident and an implied Cluster F-Bomb. Of course, given the father's reaction when he drops something heavy on his foot, it may simply have been a cluster Angrish bomb.
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.
- There's a strip where Hobbes mentions that he reads National Geographic for the hot tigress babes on the cover. Well played, Mr. Watterson. (Of course, it would only be porn if the tigresses were shaved.)
- For one show and tell, Calvin told his class that his mother dons "a patriotic leotard, a cape, and knee-high, high-heeled boots, and she fights crime as a super-heroine" In the last panel, as his mom is handing his dad the note from the teacher, he remarks, "Wow. Show me that outfit sometime."
- During Uncle Max's visit, Max was asked whether he had kids and he says no, he wasn't even married. Calvin asked what difference that made, prompting Max to mention that Calvin must watch a lot of TV, while Calvin's parents looked shocked.
- This strip. Not many non-German kids are expected to be familiar with the phrase "Jawohl, mein Führer!"
- An early strip showed Calvin asking Hobbes the meaning of a long word in a book he was reading. Hobbes saw it, immediately became so shocked that his fur went all bristly, and then recovered quickly and said "I don't know." If you think about it, there's only one 12-letter word in the English language that could get a person (or tiger) to react that way.
- One wintertime strip had Susie building a snowman with long hair and bumps on the chest; when questioned by Calvin, she explains that it's actually a snowwoman. The last panel of the strip has Calvin building a snowman, visible only from the back, with his exasperated mother declaring " I don't care. We're not having an anatomically correct snowman in the front yard."
- When his mom is sick, Calvin asked if that's because she's going to have a baby. His dad replied not that he knew of...
- After they go to the zoo, Calvin delightedly talks about something the monkeys are doing, asking why he isn't allowed to do that in public.