Dr. Seuss, when asked "Where do you get your ideas for books?" answered as follows. His answer wins, hands-down, for the best answer I've ever heard to this question. Thanks to Anita Silvey for publishing this in Children's Books and Their Creators, taken from The Horn Book Magazine in 1989.
"This is the most asked question of any successful author. Most authors will not disclose their source for fear that other less successful authors will chisel in on their territory. However, I am willing to take a chance. I get all my ideas in Switzerland near the Forka Pass. There is a little town called Gletch, and two thousand feet up above Gletch there is a smaller hamlet called Uber Gletch. I go there on the fourth of August every summer to get my cuckoo clock repaired. While the cuckoo is in the hospital, I wander around and talk to the people in the streets. They are very strange people, and I get my ideas from them."
Silvey, Anita. Children's Books and Their Creators. New York: Houghton, 1995