They also can happen mid-battle. Seeing your ninja character get hit by a Jack-O-Lantern's Jacknife attack, being stabbed multiple times in mid-air and then thrown to the ground with a bang, only for 'Miss' to appear always makes me chuckle.
Not actually part of the story yet hilarious nevertheless: In Disgaea 3, there's a brand new class called the "Superhero". He not only has one of the largest movement and jump stats in the game, but he can go through enemies much like flying characters. However, there is one oversight in his sprite animations: he doesn't jump. Instead, he merely slides up the wall using his normal standing animation.
Actually, that's what happens with all Flight-type movement characters. Give Asagi her "Sky High" Evility, which gives her the same properties as a flight-type character, and watch her Air Guitar her way up the wall.
The item descriptions. ALL of them. Highlights include, but certainly aren't limited to:
In Prinny 2, when the Prinnies finally trap the Phantom Thief, he decides to use the Omega Ice Cool spell to summon the Spell Keeper, Joshua. However, instead of instantly unleashing powerful ice magic, she clumsily drops onto the stage, apparently busy reading a magazine, and answers a call on her cell phone. While she does lend the Phantom Thief a little help in the form of random ice magic, she spends the entire battle on the phone!
What makes this better is if you listen closely to Joshua's conversation (it's encoded into the background music, so you can pause the game and hear the whole conversation). It's full to the brim with a bunch of references to the events of previous games.
The "End Turn" Running Gag in the tutorials where the player's turn ends early and the main character gets completely surrounded by all the enemy units and pummeled to death due either to curiosity or the amusement of the other characters. Mao deserves special mention as he ends the turn himself; Killia deserves mention because he survives.
The On the Next segments have been a recurring source comedy throughout the Disgaea series (minus Disgaea 2) due to the random Shout Outs and their nonsensical nature that has almost nothing to do with the game's plot. The rest of the cast taking potshots at the ridiculousness of it all (and occasionally hijacking its narration) only adds to the humor.
Lifting and throwing can create plenty of these:
With few exceptions, anyone can lift anyone else. That's right, your Squishy Wizard of a healer can lift up that muscleman who's been given giant status and throw them several panels down the field.
The fact that throwing your allies is actually the best way to get them across the field.
One character's already holding up another? No problem! You can have someone pick those characters up to create a totem pole that can reach even farther!
Dimension 2 actually made that bill practical, as not only is there a special Senator that could sway the vote through unique effects (such as extra bribes, charming Nay voters or putting said voters to sleep, thus eliminating their vote), the money given upon success was based off enemy level. This meant that in the post-game, you could flip the Cheat Shop to 20-star Land of Carnage, bribe the special Senator to sway the vote in your favor, and then rake in billions of HL!