Damon Knight, Kate Wilhelm, Thomas M. Disch, Judith Merril, Lester del Rey, Anne McCaffrey, Arthur C. Clarke, Frederik Pohl and many, many more made the afternoons and evenings at Arrowhead merry and stimulating.
There were sleeping bags on the expansive porches, bleary-eyed writer-folk sitting around the kitchen table come morning (or afternoon...) and many a story idea was expounded, dissected, and fleshed out.
Instead of the cleaning and reprimand that one might reasonably expect, within a year, the entire bathroom had been covered floor to ceiling by remarks from eminent science fiction writers, agents, and not a few fans.
The walls, the ceiling, the shower stall, even the sides of the bathtub did not escape from the onslaught of writers who found a tabula rasa, no matter if it was only a tiny clear space.
Only one graffito escaped the purge, and still remains as of 2005; an electronic diagram for the RF output stage of a pirate AM radio station on the back of the bathroom medicine cabinet door.