In the climax of It's a Mad, Mad, Mad, Mad World, the main characters dangle off of a fire escape and then all fall down in various painful, and yet very funny manners. Also, Mrs. Marcus's tripping on the banana peel, but this is because she's a horrible shrew.
The James Bond movie Live and Let Die has an amusing death scene at the end. Bond pops a compressed air pellet into the mouth of the villain with alarming and jarring effects: he literally swells up like a balloon and hovers up into the air, where he continues to expand until he explodes with no gore whatsoever. Such a sudden, cartoonish moment in a movie that has so far been at least vaguely grounded in the laws of physics was a bit hard to stomach for most. It's no surprise that this was Roger Moore's first Bond movie, signifying the beginning of a sillier, more outlandish Bond than before.
Played with in Death Becomes Her. Two women had taken an eternal youth potion. But being unable to die, well, one falls down a staircase and ends up with many injuries (the ER doctor makes a list of them and shortly later has a heart attack), the most prominent a broken neck; and the other is shot by the first in the stomach, leaving a fist-sized hole clear through her torso.
Tony Stark sets the suit's thrusters to ten percent power, and is slammed against the ceiling hard enough that, realistically, he should have broken at least a few bones... from that or from the subsequent face-first fall on the floor before getting sprayed by an automated fire extinguisher.
Then, there's the scene when Tony's assistant, Pepper Potts, walks into his lab just as he's testing one of the repulsor beams in the suit's gloves. The recoil throws Tony offscreen and you hear him hit the far wall a couple seconds later. Pepper's reaction, mainly her complete lack of concern for his safety, is what really sells it.
The Three Stooges were famous for getting into goofy slap-fights and otherwise injuring each other (and themselves) in an amusing fashion. (Joe Besser, for some years working with them, claimed that the left side of Larry Fine's face was noticeably coarser than the other side, which he attributed to Moe's less-than-staged slaps.)
Space Jam uses it not only with the Looney Tunes, but with the live-action actors - Michael Jordan is curled into a ball, and Wayne Knight is crushed flat.
The Home Alone movies practically ran on this trope, subjecting Harry and Marv to traps that would have killed or maimed them very badly. Wrestler and author Mick Foley, who loves Christmas and everything related to it (the first two films happen on Christmas), once had a doctor review Home Alone 2 with him. The doctor concluded at least half of the traps/injuries the villains experience would likely have killed them instantly in real life.
MouseHunt: Much of what happens to Ernie and Lars(and Caesar and Catzilla).
Larabee gets a paper stapled to his head twice in the Get Smart movie by Agent 23 as retribution for not unjamming the photocopier.
Laurel and Hardy lived this trope in their movies — though one scene in The Music Box looks genuinely painful: Stanley, pushed once too often, pokes a finger in Ollie's eye — then, staggering in pain, Ollie steps on a nail in a board that sticks to his foot. Gaaah.
Loki, poor Loki. In The Avengers, during the battle near the end, he tells the Hulk about how poorly he thinks of him. Hulk doesn't like it, and proceeds to smash him around, turn around and call him "puny God". Bonus points for Loki waking shortly thereafter, captured but instantly alert and snarky, in a Loki-shaped depression in the floor.
Bifur from The Hobbit trilogy has a piece of a pick axe embedded in his skull, as seen here◊. Also Dwalin's right ear looks like someone or something took a large bite out of it.◊
Rita: I've tried everything. It doesn't work. Cage: Have you tried... you know... all the options? Rita: Oh you mean sex? Yeah, tried it. Cage: How many times? Rita: All right. (pushes button — robot slams Cage across the room)
Done multiple times to the title character in Deadpool, due to his powerful Healing Factor and nigh-immortality. For example, when he tries to attack Colossus, Deadpool ends up hurting himself in such a ridiculous manner that even the normally moody Negasonic Teenage Warhead can't keep a straight face.
In Ogginoggen, young girls Ida and Klara stuff jellyfish down their shirts to create Gag Boobs. Of course, then they both get stung, sending them running off to the showers.
This is a Running Gag with George in Scary Movie 3. Among others, Cindy comes home to find him slumped down on the table and has to shake him awake. She asks him what happened and he says that he and her son Cody were playing a fun game when... then he looks down and... "Ooh, Yahtzee!" (stands up and bangs his head on a shelf) Also, later when he meets the aliens, they choke him because it's how they say hello. And then there's how they say goodbye.