Just spotted this: Bookninja has posted a handwritten sheet of densely scribbled ballpoint - JK Rowling (AKA Lord Volderowling) laying out the plot of Harry Potter and the Order of the Phoenix.
Niiiiiiiice. Totally worth squinting at for a couple of minutes.
Just remembered recently discovering one of these that I did back in college: nowhere near as orderly. In my recollection it consisted mostly of a slightly woggly line curving downward with an arrow somewhere in the middle indicating the introduction of a character, and a cloud of scribbles at its beginning. Now I really want to go home and find it. If I do... I'll post it.