Are you a fan of Edmodo? Use their badges to create a rewards system in your classroom. These certificates help students/teachers keep track of redeemed badge rewards and are fully-editable! When students reach a badge milestone, I issued the appropriate certificate to them to redeem at the time of their choosing. My kids loved this system and yours will to! Have fun!
Be sure to check out the accompanying Edmodo Rewards PowerPoint presentation and Edmodo Rewards Posters.