These are mostly suited for the younger students but can be adapted for older classes.
Work with students to come up with a set of classroom rules and consequences.
Have a pocket chart with all students names on it. Beside each name have a pocket where either a red, yellow, or green card will be display. Red=some sort of consequence decided and explained earlier.
Green=You're doing great.
Punch Out Card
Each child receives a pad of paper. Whenever they are performing well, helping out, etc.., give them a punch with a one hole hole puncher. When students reach a certain number of punches, they can pick from a box of prizes.
Display a tally system of points on the blackboard. Every time students are performing well, give them a point. When the class earns a certain number of points by the end of the week, they get to do a class fun activity at the end of the week.
If the class is doing well add a marble to the marble jar. When the jar is filled, they get to do a class fun activity. Count the marbles regularly as a regular math activity.
Positive Popsicle Sticks
Write out positive comments on popscicle sticks like "great helper", "super effort", etc., and hand them out accordingly. When each student recieve a certain number of popsicle sticks they can get a reward.
Good Behavior Chart
As a class, come up with a list of good behaviors. At the end of the day, go through each one and ask the class how each was demonstrated in the classroom during the day. Then, as a class thank the student who accomplished it.