Theme : Unusual Styles

I have just finished "The Three" by Sarah Lotz. It wasn't a story that I got into particularly well but the author bravely wrote in a very unusual style, telling the story by way of third party emails, reports, phones calls and so on. It was refreshing to read a book where the writing was not just a conventional storytelling. I have enjoyed books in the past written as diaries, letters and so on. Which books can you recommend that have been written in an unusual way?