A simple and effective starter activity is to get students to create a quick quiz to recap their learning from the previous session. They should then pass this on to a partner. You can set the parameters to make it as simple or as complicated as you like!
Why? If you sit up the night before creating the quiz not only are you adding more work to your already ridiculous workload, but you are depriving the students of a vital learning opportunity. Thinking about questions takes their learning to a different level and, as they are writing the questions, they are revising the material.