Monthly writing journals. Great to show growth, like portfolios! I'm thinking pass back writing month by month and have students select their two or three favorite pieces. This gets to the judge and evaluate level of Bloom's.
Editable quick reference flip book to help substitutes find the most important info they need about your class at a glance. Print on brightly colored paper and hang in a prominent location near your desk so that a new substitute can easily find it, and have necessary information at his/her fingertips!
Classroom Set Up - Encouraging Collaboration and Self-Directed Learning. This post if full of pictures and ideas. I love how there are so many different places for students to work, and everything is so inviting!