Moving Pictures by Terry Pratchett

This book parodies the siren call of the silver screen, as the whole Discworld is turned upside down when the last of the Doorkeepers dies, the Alchemists discover octo-cellulose, and enterprising individuals flock to Holy Wood. There are lots of great moments sending up classic Hollywood movies (Gone with the Wind, Snow White and the Seven Dwarves, and Ben-Hur, among others). Very funny.