As a hard workin' sub, I was glad to hear all you 'regular' teachers throw in for us. I know subs can be lazy, but I have to say, after four years of living off of subbing for elementary schools in LA, it doesn't get much easier to manage a class you don't know. I do a lot of art with the kids. But it isn't with every class that I will get too involved with materials- it just gets too chaotic, and takes more prep time than I often have. I do a lot of drawing from observation projects with just pencil and copy paper, and invention designs too (invent a robot, invent a super-shoe, design a costume to portray an emotion). These have saved me from many an unruly class with no lesson plans or much for supplies on hand. Today I did a lesson with 5th graders, having them draw everything they could see while staring at one thing, starting from the outside edges of their field of vision and working inward. That occupied them for a while!
So, the only advice I have is:
1. If your room is neat and organized when we get there, it's a lot easier for us to make it neat and organized when we leave.
2. Leave simple activities as easy back-ups in case more complex plans runs into snags.
3. Leave specific consequences for behavior problems, so you and the sub are on the same page.