I have worked at various grade levels 5 to 12 doing reader's theatre with James Thurber's Fables for Our Time - "The Little Girl and the Wolf," "The Unicorn in the Garden," "The Owl Who Thought He Was God," etc. My students and audiences alike have always enjoyed them. They're short and funny, and can be cast flexibly. You can assemble as many or as few of them as you need to fill out the length of your program. Good luck!