I love this idea from The Clutter-Free Classroom. If you know you are going to be away get your students in groups to write down classroom expectations. As a class, you make a list of the really important ones. When you have a supply, she/he can read the expectations right in the morning so they are all on the same page.
SUB PLANS: In your sub binder put the book “Miss Nelson is Missing” and have the substitute read the book to your class. Have the children then write a story about where they think you are while you are out from school. I can only imagine how funny and creative these stories will be!