Calvin once responded to the test question "Explain Newton's First Law of Motion in your own words" with, "Yakka foob mog. Grug pubbawup zink wattoom gazork. Chumble spuzz."
Another example in class:
Mrs. Wormwood: CALVIN, PAY ATTENTION! We're studying geography! Now, what state do you live in?
Mrs. Wormwood:(sigh) I don't suppose I can argue with that...
Calvin plays Monopoly with Hobbes and takes money from the bank. When Hobbes points out that there's no rule saying you can rob the bank, Calvin counters that there's no rule saying you can't rob the bank.
Calvin lampshades the "No Shirt, No Shoes, No Service" sign on a restaurant by saying he's going to just walk in with no pants. Hobbes points out that he'd probably get a court summons.
Employed by Peter where he writes a book report three pages long in a massive font. Apparently, the teacher didn't say anything about font size.
Paige and Jason ate all the cookies while blindfolded, so that they could answer no when their mother asked if they "saw what happened to the cookies". (Of course, they would have been screwed if she happened to word the question differently.)
Paige asks if she can have a snack before dinner, Andy naturally says no, so Paige asks if she can have a banana, Andy says yes. Paige's response?
Paige: Of course, I'll have to eat this entire loaf of banana bread to GET at the banana...
Paige is allowed to have one scoop of ice cream... then takes all of the ice cream out of the box in 1 scoop. Having the entire Fox family use these kinds of loophole abuse is a Running Gag for the strip.
Jason asks his mom if he can have his Halloween candy before dinner, specifically reassuring her he means ONE piece.
Peter:(when Jason pulls up a giant lump) I wondered why you put your bag near the radiator.
Lampshaded in one strip where Andy is upset that Jason is playing a racing video game instead of setting the table like she asked him to. Jason had asked her to allow him to try the game "for a sec" - but he meant parsec, and had only traveled 46 of the 19.2 trillion miles Andy had "approved". At the end he is grumpily setting the table complaining, "Well, I'd call it a valid loophole!"
When Jason asks his parents if Marcus can come over, he realizes he's been put in a loop of "ask your mother/father" and has to consult a logic textbook.
In Scott Adams's first book, The Dilbert Principle, he notes that this strip was based on an actual situation that a reader submitted. The submission noted that the result was an immediate "underground bug economy" and the program was scrapped after one employee got a $1700 bonus the first week.)
In one strip where the eponymous cat is on a diet, he invokes this trope when he realizes a cake is carrot cake.
The time Jon tried to teach Garfield self-control. He left a box of kitty treats in the room Garfield was in, telling him not to touch it. He left the room, then reentered a short while later. Garfield took everything out of the room except the box.
Even more audacious when Garfield was on another diet and Jon told him "You may have a salad." Garfield promptly helped himself to some pork chops, and when Jon called him out he claimed that no one had ever told him that pork chops were not a salad!
And once again: "This salad needs something. I think I'll garnish it. With a ham!" *wham*
And yet again (Garfield does this all the time, and Jon knows it):
Charlie Brown: <words to the effect of "Okay, I guess you mean it this time."> (e.g. "It is signed! It's a signed document. I guess if you have a signed document in your possession, you can't go wrong. This year I'm really gonna kick that football.")
[Lucy pulls the football away yet again]
Lucy: <insert explanation of the loophole she left herself> (e.g. "Peculiar thing about this document — it wasn't ever notarized.")