..but it's the first that comes to mind.
Choke by Chuck Palahniuk is a dark, perverted novel. This is why it is so bloody good.
The book follows a guy, Victor, during a couple of months of his life. Victor is a sex addict who makes strangers into heroes. Every night he will go to a restaurant and 'choke' on his food, allowing a stranger to save his life. Obviously this isn't a completely selfless act, the people who save him regularly send him cheques which helps him to pay for his dying mothers care home.
His best friend, Denny who he met at a support group, is trying to overcome his sexual addicton by collecting rocks.
The story has flashbacks to Victor's childhood and the strange and illegal activities his mother made him do. Turns out she was a bit nuts.
oh and i forgot, Victor is lead to believe he is the descendant of Jesus.
It is a very strange story, but it does not get boring. Read it.