Turning up in a "traditional piratey town" only to see buildings such as Starbuccaneers and Planet Threepwood.
The "Pirate School" on Knuttin Atoll.
Admiral Casaba's McCarthyism-style paranoia about pirates.
You can also talk to Murray... Or make him spin around on his pedestal, which annoys him. There's absolutely no productive reason to do this. It's just funny.
Murray: If you don't stop spinning me, I'm gonna put an eeeevil curse on you! (Guybrush spins Murray again) That's it! You're cursed! You are gonna have such a rash!
You can optionally kill Guybrush's future self (twice) in the mists of time and his hilariously casual reaction.
Guybrush: Gee, they're right... gun owners are five times more likely to shoot themselves.
"No! My grog!"
This exchange from the first act:
Carla: Do you have any idea how difficult it is to escape from Monkey Island? Guybrush: No, how difficult is it to... Escape from Monkey Island™! Carla: ...Well, it's... really difficult.
The Dainty Lady Figurehead. Voiced by Pamela Adlon
Dainty Lady Figurehead: What is this compulsion you have to dress me up, you pantalooned FREAK?
When Guybrush rides the lava flume ride, he will sometimes sing a little song:
Guybrush: The temperature's a-risin' And my sweat is vaporizin' And I cannot feel my legs below the knees any more! Oh, the lava is hotter Than a flame-broiled otter And my shoes are slowly melting to the fiberglass floor!