Literary surprise

I've never come across a book that suddenly turns into a musical before. That is until I read a specific chapter of Neal Stephenson's Quicksilver last night. All was normal until a sleep deprivation, but mainly syphilis, induced psychosis (the character in the books, not mine!), brought about a veritable Les Miserables style song and dance, including extras galore consisting of dancing skeletons, priests, slaves and fishwives! I'll write a proper review of the book when I've finished it, but I really recommend people read it.