In "L'ivresse" ("Drunkenness"), a Livre II episode, we're shown some of the main characters drunk. Starts with Bohort calmly suggesting they let him kick the crap out of a rival clan chief, and tops it with Perceval passed out on a tavern table suddenly raising his head and shouting "Independent Wales!" at the top of his lungs.
The Ankou showing up in the middle of the night to take the body of a recently dead servant, and ending up drinking "one more for the road" with Arthur.
Arthur finding out that Perceval is alive after hearing he died. "But you're not dead, you bastard?!"
Any episode with Merlin is bound to have one of those.
EVERY. SINGLE. THING. The Burgundian king has ever said or done. Especially when he starts singing.
The taunts used by the Weaponmaster are so deliciously gross, they all belong in there. Here's a few examples:
Weaponmaster: Come on, on guard, sweetheart! I'm gonna cut the fat out of your ass, that's one thing you won't have to carry any more!
Weaponmaster: Buck up, pumpkin ! you're gonna get your ding-a-ling sharpened to a point!
Weaponmaster: On guard, you old balding whore!
"La Quinte Juste":
Father Blaise: The next person I catch whistling a pagan interval, I'M REPORTING HIM TO THE POPE!!!
Father Blaise: (reading a book to Karadoc) The respective wives, should be presented... (cue Karadoc sleeping, starting to snore) Father Blaise: ... Ho! Karadoc: (wakes up) Huh ? Father Blaise: Say, are you bloody kidding me?? Since this morning, you've been busting my prunes because you wanted me to read this to you, and now you're sleeping??
(exiting his office building with his right-hand man, after a fight with some senators) Sallustius: (twitching and stuttering) LAST SEASON FOR THE MORONS!!! Get the tools, we move on from negotiation to disintegration. Capito: The four of them, at one stroke?? Sallustius: At one stroke. Collective ass-kicking. Capito: Wouldn't it be a bit obvious? Sallustius: I don't give a damn. You can crucify them on the forum, if you want; I will pay the orchestra.
Léodagan, thanks to the marvelously deadpan delivery of his actor, can have some of the funniest lines — on the condition that you appreciate Black Humor. Especially during his spats of Tranquil Fury.
The one most rolling-in-the-floor-in-laughter-worthy time: after being kept awake for hours by Yvain and Arthur playing the lute, Léodagan comes in and, deceptively calm, describes how he's about to start putting things on fire — maybe the whole castle while he's at it.
Léodagan:Even the furnitures! Doesn't scare me.
Perceval finds an oud abandoned by Gipsies ("Their crossbows sure look weird"). When Arthur starts playing it at night, Léodagan yells at him to shut up. He gets maybe ten seconds of respite before Arthur starts playing again... while singing. Léodagan's (lack of) expression is priceless.
There is also the one time when, following rumors of the death of the king and queen of Carmélide, they discover that the culprit is Yvain and his (latest) poor choice of a nom de guerre* He's been going around calling himself "The Orphan of Cameliard", thinking of the great big grey animal with a really long nose.... Cue Léodagan threatening his son with a crossbow, Arthur (with a small wooden shield) and Father Blaise bodily protecting the young knight, while Séli (half-heartedly) tries to reason her husband. Father Blaise explains that they'll produce a disclaimer... but can't help adding that the news won't make everybody happy. Fade to black, and there's the sound of a bolt hitting wood.
Also, you won't see many scenes with both Léodagan and Loth before Livre VI. But when there is one...
Léodagan: (completely deadpan) Tell me, aren't you supposed to be under house arrest, you very big pile of dung?
From one of the pilots: two Vikings show up and demand tribute lest they destroy the castle. Arthur gives them a spoon.
Arthur: Here. It's a relic. It has immense value. Sven:It's a spoon!
Léodagan: A room full of bags of gold — and to guard the whole thing, a six-headed hydra. Arthur:A six-headed hydra?! Léodagan: Yes, your majesty! Myself, I've already done a four-headed one, well it wasn't a walk in the park, I can assure you. Arthur: I've done a six-headed one, once. Léodagan: Ah yeah? And so... Arthur: I nearly got wasted. Léodagan: Oh? Arthur: And we were three. You're sure about this? Léodagan: Well, to tell the truth, I asked for something hard, so we could gloat a bit when we'll be back... Arthur: Yeah, but with a six-headed hydra, we aren't going to gloat for long, I can tell you... (later, in the dungeon) Arthur: This place is familiar... Léodagan: You'll comment the visit another time. Arthur: No, no joking, I feel like I've already been here... Léodagan: Of course not! Once inside, all lost temples look alike. Arthur: What did you tell me it was called, already? Léodagan: I couldn't have told you, I don't know. Arthur: Wouldn't it be the Temple of... Mylère?... Léodagan: Méhilir! No, no, that's it, the Temple of Méhilir. Okay, are we butchering this hydra, or do we just camp here? (Arthur sheathes Excalibur) Arthur: That's the one hydra. Léodagan: The one what? Arthur: The one I killed. There's no hydra here for a good while already. Léodagan: Well, that's perfect! All we're left to do is pick the dough. Arthur: You don't think I've fought a six-headed hydra just to leave empty-handed, do you? I took everything. Léodagan: What? (Arthur nods) Is that a joke?! Arthur: No offense, but your information is a tad dated...