The ending of the first game; Jim makes it to Princess What's-Her-Name, and she puckers up to grant a Smooch of Victory and the cow you sent flying up at the beginning of the game lands on her, knocking them both into a river/pit of lava. Jim mopes for a moment...then grabs her crown and happily wanders off.
The ending of the second game; And so, having defeated the nefarious COW, our hero, COW, wins back the heart of the lovely COW. In other words, Jim, the Princess and Psycrow — aka the hero, the love interest and the big bad — all turn out to be cows in disguise.
Anything involving a cow deserves special mention (particularly the second game's ending, where it's revealed that the Big Bad, the Distressed Damsel, and The Hero are all actually cows).
Or anytime Jim goes into Large Ham mode. Which would be about 90% of the time.
"''Eat dirt, everyone in the vicinity!! AHAHAHAHAHHAHAHHAHAH!!"
At the beginning of "Conqueror Worm", Jim and Peter are hanging at the Terlawk Mall with The Mighty Hamstinator. However, Hamsty can't get over his habit of stuffing random things in his cheeks, leading to this line...
Jim: Hamsty! Get that cheese hostess out of your mouth! You don't know where she's been! Ishy! Ishy!
As Jim, Peter and Snot have to retrieve the suit.
Narrator: ...But how can our heroes ever hope to get past the sinister guards? (Jim, Peter and Snot calmly stroll by) Peter: Evenin', guys! Guard 1: Evenin'. (beat) Did a giant worm, a talking dog and a smiling booger just go by? Guard 2: Yep. Guard 1:(picking up the phone) Hello, DNA lab? Whatever you guys are doin' in there, CUT IT OUT!
During the fight:
Jim: I've been thinking about this whole "exact opposite" thing. Since I hate losing, you must love it! So why not give up right now? Evil Jim: Oh, don't be so literal-minded.
"Feel the awesome power of your own left fist!"
The Enchanted Snail Petting Zoo.
Jim: I think they like you, Peter. Peter: THEY'RE DEVOURING MY FLESH!! Jim: [laughing] Well, that just proves it.
At the beginning of the Christmas Episode, Jim gives Queen Slug-For-A-Butt a present.
Queen: For me? You shouldn't have. (She opens the box which blows up) You gave me that LAST YEAR!