I have created individual charts with the planets. Each chart increases by 10 points. This is a good challenge for the students. You can purchase the space shuttles to go with them as well. Once you put the first space shuttle with their name on it rest of the students want to follow. You may change the points if you want to fit your class goals. My reward for getting to each planet is a free homework pass. Make sure to print on card stock paper and laminate for durability.