FYI. I created a great reward for my students. I created a lottery type scratch-off, if the students get three matching symbols they are rewarded with bonus points (for tests & quizzes), take a quiz off, and other prizes like donuts for the class. They earn the tickets by answering questions in class. It motivates them to work outside of class to be prepared.
If you would like more details, email me zawora@antonelli.edu