Funny: This Book Is Full Of Spiders Seriously Dude
Whenever Amy shoots something with the Furgun.
In the epilogue, when Lance Falconer and David Wong describe how they're going to fabricate details in their account to make "Lance" seem cooler, shortly after "Lance" begs David not to make him say or do anything ridiculous the next words out of his mouth are that he's going to get his pubic hair bleached and straightened so that his penis will look like Santa Claus. It's best not to be drinking anything while you read this book.
When Detective Falconer arrived at Dave's house and sees Dave standing naked in his driveway, covered in blood, high on amphetamines, and covering his crotch with Franky's severed head. After the seriousness of the last few pages, this situation is jarringly funny, because it's so unexpected and out-of-place:
Falconer: "SHUT UP. Both of you. You're coming with me. Put some pants on."
Dave: "Fuck you. This is my house. I make the rules. You take your clothes off. John, get the Twister mat."