Murgo the trader's sales pitch at the start of the game, including hawking a "magic" mirror that makes you look more attractive, but only if you look into it in complete darkness.
One of the loading screen tips includes a hilarious Take That, Scrappy!, which mentions a rumor that during the fall of the Heroes' Guild, the Guildmaster was found dead with the words "YOUR HEALTH IS LOW" carved into his forehead.
What about at the very end, if you let Lucien talk for long enough? Reaver stands, shoots him in the face and says "Oh, I thought he'd never shut up! Sorry, did you want to kill him?"
A child might say something like this: "If I hold my breath for 30 seconds, I can see funny stuff".
One quest has you go into an ancient tomb to find an old woman's son, Charlie. Then it turns out "Charlie" is a full -grown man and a professional explorer, and his mother is just being overprotective.
Flavor Text does NOT take itself seriously in this game. For instance, on the Worn Comfy Chair:
"The weight of many arses has worn a nice groove for you to settle into."
During the prologue, one quest has you deliver a love letter from Monty to his beloved Belinda. You can take the "evil" option and give it to Belinda's cruel and overbearing mother instead, which causes the old woman to storm out, confront the would-be paramour and give him a tongue-lashing. Monty tries to claim that the letter was intended for the mother, and is mortified to find the woman apparently reciprocates his "feelings"...
The Hero's "Joke" gesture involves him performing a hand puppet show, even providing cute little noises for the hands. It needs to be seen to be believed. The best part? It causes everyone who sees it to laugh, even enemies in the middle of a fight!
Jasper in general tends to be hilarious. When you get the Normanomicon:
"Ah, the Normanomicon. As a young boy I often heard tales of its sinister exploits and prayed dearly that I would never encounter it myself. Incidentally, thank you for bringing it into my living quarters."
The Mistpeak Valley Demon Door is writing a book, and needs two heroes to act out romance for him so he can write it. He sounds like a gentlemen, but after you finish he tells you:
Demon Door: Thank you! Now when the two characters shag at the end, it will pop right off the page!
If you listen to the bandits who robbed a carriage carrying a gargoyle long enough, they'll eventually start debating philosophy absolutely seriously, with the terminology and everything, trying to justify robbing a carriage they weren't paid to rob that wasn't carrying any money. Philosophically. Glorious.
The one time when Walter got past a magical barrier set up by a Hobbe. He shouted BOO and the Hobbe was so shocked that the barrier it was keeping up disappeared. And then it died of a heart attack.
One of the sword finishing moves on hobbes is to point behind them. The hobbe actually turns around and you slash their back.
That's nothing. Another Hobbe finishing move is to punt the little sucker.
Using a hammer against them, well, here's the pitch, HOME RUN MOTHERFUCKER.
You think that's funny?! What about the pistol thing? When you're fighting a little Hobbe, if you attack it with a pistol at a certain range, it jumps up, and tries to eat your arm. Then, you pull the friggin' trigger, with your arm down its throat!
Also kicking them into the air and shooting them with your rifle into the opposite cavern.
Enemy chatter when you use finishing moves, kinda hilarious when theres one guy left and he sounds crazy scared...then bum rushes you.
Since you can still hear other people during sex, this line can and will come up if you do so near a weapon shop.
Wife just gives a sigh of contentment when a shopkeeper yells "We sell melee weapons of all shapes and sizes!"
Anything during sex is funny because people are seriously just standing around WATCHING. But your character is like "Doesn't matter...Had sex!"
Every single time you make one of the "moral" decrees rather than the "profitable" ones, Reaver makes a hilariously tongue-in-cheek public service announcement trying to put a positive spin on things... from his own twisted point of view.
At Reaver Industries Orphanage, we care. Even if you don't deserve it.
After reaching the shores of Aurora, the Hero and Walter start walking into a cave, wherein Walter says a few funny lines, starting with the shouting of his pseudo-catchphrase "balls." Laugh now, because it goes downhill from there.
Lemmy's comments when you do terribly at the shooting range are hilarious.
Have you been drinking? If not, you should try it — it couldn't hurt.
Barrel might be out of alignment. Or maybe you just don't shoot very well.