The "how much wood could a woodchuck chuck" conversation between Guybrush and a carpenter.
Guybrush: How much wood could a woodchuck chuck if a woodchuck could chuck wood?
Woodsmith: A woodchuck would chuck no amount of wood since a woodchuck canít chuck wood.
Guybrush: But if a woodchuck could chuck and would chuck some amount of wood, what amount of wood would a woodchuck chuck?
Woodsmith: Even if a woodchuck could chuck wood and even if a woodchuck would chuck wood, should a woodchuck chuck wood?
Guybrush: A woodchuck should chuck if a woodchuck could chuck wood, as long as a woodchuck would chuck wood.
Woodsmith: Oh, shut up.
And the Call Back to this is equally hilarious when Guybrush asks LeChuck, who cuts him off and answers "Seven cords."
The Wanted Poster on Phatt Island, especially towards the end of the game.
WANTED: Guybrush Threepwood: For the murder of G. P. LeChuck, and also for the use of witchcraft on the person of Largo LaGrande, the thievery of clothing and medically-prescribed hair supplements for such witchcraft, graverobbing, trespassing, larceny without a permit, disturbing the peace, illegal gambling on a sporting event, use of falsified identification for the purchase of alcohol, exceeding allowable FDA limit for rodent parts in vichyssoise, premature entombment of a non-dead individual, reckless tampering with city-maintained plumbing without prior acquisition of environmental impact report, transportation of animals not in a mental state to give consent, vandalizing a historical miniature, reckless use of gardening tools, impersonating a woman in order to evade prosecution, two counts of unauthorized exiting from a penal institution, impersonating a federal mail boat, reanimating dead persons within city limits, possession of library books not specifically checked out to oneself, mixing drinks without a liquor license, and releasing a dangerous reptile in a populated area.
Also wanted for questioning regarding the disappearance of prescription eyewear.
Guybrush lighting the match in the dark room of LeChuck's fortress. And the explosive aftermath.
Stan and the coffin. It would be reprehensible if it weren't Stan.
Even then, it's still kind of a dick move, but at least it sets up a nice Brick Joke for the sequel.
The part in LeChuck's fortress where Wally and Guybrush are hanging marks one of the few times where death is actually possible. If you wait too long, the trap is set off, with Guybrush and Wally sent to their doom screaming in pain (the voice acting in the Special Edition only makes this even more hilarious). Of course, by this time you've forgotten Guybrush is actually reciting how he made it to where he is, which leads to Elaine lampooning him for trying to convince her that he actually died.