While it may be an overused song in movies and TV, What a Wonderful World plays as Harold is taking a shower happily dreaming of kissing Maria over and over again....right until he hears and smells Kumar shitting in the toilet right next to him.
The KKK are arguably the most well-liked comedy part of the movie.
One KKK gay shouts how much he knows about the peoples he hate so much: "Send them Indians back to Africa!"
Kumar: I took a Ko-re-an guy's toothbrush, and rubbed it all over my diiiiiiiiiiiiick.
Harold: (concerned cause he's that Ko-re-an guy) Dude, you did that?
Klan Leader: Now that's just damn right disgusting. But I like it!
"Dude, the klan is fucking slow."
The clan even make their own white dog wear a KKK hat.
The leader is so racist that hearing the pains of his own men make him ask "What the nigger was that?"
The leader sets himself on fire, badly, and it burns all of him alive as he runs around dying. The rest of the clan, who appear to have invested so much loyalty in him, just stand watching in awe as one questions, "Should we put it out or what?"
When the old woman sees Kumar sitting some seats ahead of her, she briefly imagines him with a beard and turban, laughing at her, and imitating an airplane with his hand, falling out of the sky and making an explosion sound.
The scene where Neil Patrick Harris does mushrooms and has a vision of himself on a unicorn. Even better, he's being questioned by a police officer the entire time. Not once does the cop even suspect that anything is wrong.
The racist (and apparently anti-semitic) Agent Fox tries to break Rosenberg and Goldstein during interrogation by slowly pouring a bag of pennies out on the table in front of them. What makes it more hilarious is Rosenberg's actor can barely contain himself throughout all the takes.
At the brothel, Harold is telling all the prostitutes about how much Kumar has been screwing up the whole journey through and is probably thinking that he's having a great time having sex with the prostitutes. Cut to Kumar's room and we find him crying over losing his girlfriend while the prostitutes try to comfort him over his loss.