I've always wondered if someone had written a book in which dialog or narration was presented in a naturalistic way. Anyone who has ever read a deposition or the transcript of an impromptu speech knows how incoherent people really are when they speak.
I have found such a book, though I've only crawled through the first 30 of 700 pages. It is William Gaddis's JR. Every scene is a complicated and rambling conversation between three or more people, with sub-groups carrying on sub-conversations, characters ignoring others, time lapses in between responses to past statements. It is confusing, but also hilarious and interesting.
Incidentally, the plot involves an 11-year old who manages to build a huge paper-goods concern out of an endowment of Army surplus items using only a pay phone. It may or may not be an ultra-liberal critique of free-market capitalism.