Laugh Themselves Sick

A pretty common Real Life reaction to something especially funny is for someone to end up character gripping their stomach in pain, often while laughing hard enough to weep. As in real life, so in fiction: Laughing Themselves Sick is the most common physical response a character can have to an in-universe Crowning Moment of Funny. Some characters may remain standing, while others may have to sit down or will even roll around on the floor; the acronym ROFL stands for "rolling on [the] floor laughing".

Die Laughing is a related trope (though hopefully not too related) where the character in question actually dies while laughing, though not necessarily because of it.

Anime and Manga
"Orlando laughed so hard he hurt his jaw."
 * Kenichi: The Mightiest Disciple: In his climatic fight vs. Odin, Kenichi Shirahama starts to imitate his various masters in order to throw off Odin's Awesomeness By Analysis Kung Fu Clairvoyance. Some masters cheer with pride at seeing Kenichi imitate them, while others nervously deny that they look or sound like that - and then Kenichi delivers a spot-on imitation of Akisame Koetsuji, complete with short lecture. Akisame states his approval...while the other masters crack up. Even Kousaka Shigure has a hard time holding it in.
 * Commonly displayed by the Hikaru and Kaoru in Ouran High School Host Club, particularly when they manage to get the better of Tamaki. See the episode where Tamaki utterly fails to impersonate Haruhi and resulting Ocular Gushers from the laughing twins.
 * A short but simple example from near the end of Mattimeo

"Kunio: BWA HA HA HA HA! I thought bestiality was illegal in this country!"
 * In the Great Teacher Onizuka manga, Kunio Murai spots Onizuka walking around with an ugly, fat older woman, and has this reaction


 * An earlier episode of One Piece has Nami and Usopp dying of laughter after Zoro shoved his glass of water down Luffy's throat where the latter had flicked a booger into it.

Fan Works

 * In the Worm/Luna Varga crossover fic Taylor Varga, Amy and Taylor end up rolling on the floor laughing more than once over the plans they make. The habit spreads to the Family as a whole, whenever they do something to boggle the city.

Tabletop Games

 * In the classic D&D tale Head of Vecna, the DM 's sides started hurting when "Group Two" was falling for an obvious trap. He maintained a straight face until the second character in group two got decapitated.

Video Games

 * In The Sims 4, Sims are capable of hysterical laughter, and it's possible for a Sim to actually Die Laughing.

Web Comics

 * In Sinfest, Slick clutches his stomach while laughing.

Western Animation

 * SpongeBob SquarePants does this often depending on the episode.
 * In "Funny Pants", SpongeBob laughs so hard so often that he seems to pull something; Squidward is so tired of the annoying laughter that he takes the opportunity to convince his coworker that he's wearing out his "laugh box". On Squidward's bunk advice, SpongeBob manages to go 24 hours without laughing, only to then find that he can't laugh anymore. This leaves him in a deep depression until Squidward comes clean, which causes them to both laugh heartily - but Squidward finds it far funnier than Spongebob did, to the point where his laughter actually lands him in the hospital! Turns out laugh boxes are a real organ, and his was so barely-used that it gave out. Spongebob was thankfully kind enough to donate a part of his own... which gives Squidward the same exact annoying laugh and drives him insane.