Punch Cards for Positive Behavior - Each student gets a punch card, and when the teacher sees students with exemplerary behavior, they get a punch. When the punchcard is full, the student gets a reward.
My teacher uses a Noise Meter similar to this one. The Noise Meter is a cool way to remind students the correct noise level that they should be using! You just use the paper clip and move it to the appropriate noise level the students should be using.