Nothing makes me cringe more than the thought of being absent from school. We are currently having a terrible shortage of subs (made the front page of the news today in fact) and so instead of having one person in my room all day, there might be other teachers or administrators covering my classes. EEK! All the more reason to tidy up and make sure ANYONE can walk in and deliver a 40 minute lesson.
This year I started a sub shelf. It is eye level behind my desk directly above the printer. There is a note to the sub that is under the clear desk mat directing them to self-select from that area in the event they can't follow the art lesson for the day.
I've included the "Getting to know the world's Greatest Artist" series, How to Draw books and sub-friendly lessons (inside the binder).