For individual rewards I do a class "money" system. Each student gets their own checkbook,. and they recive class money for correct answers on HW and classwork . Every Friday we have an auction, where the kids can buy stuff. I usually get cheap snacks and toys from the dollar store. I start with an opening bid and go up in increments of $5. The kids love it (mine are 7th & 8th grade). As a group reward, they earn class points every time they are working together cooperatively, get tasks done on time, or just generally are considerate and appropriate. I like to make it a point to tell them why they are earning, so they understand what behavior got them the points in the first place. We set a goal for 25, and when they reach it we do something special together, like a free computer period or extra PE, or even a movie. You can even start an activity off with a goal by telling them if they can do such and such assignment in a specific amount of time, or quietly, you'll give them so many points. Hope that helps