This game only requires a small magnet and some chalk or a marker.  What you do is draw a line with five evenly spaced intervals on it on the white/black board.  Put the marker in the middle to start. A happy face or drawing of something nice can go on the good side, and a frowning face or something bad can go on the bad side.
If the kids are naughty, then you move the magnet toward the bad side.  If they are good, you move it  toward the good side.
If it goes and stays on the bad side by a certain time, some kind of punishment can be doled out.  Somehting like no game, or maybe even homework or extra homework.  If they are good they can play the game, get less homework, or whatever nice surprise you have in mind for them.
Kids here are usually very competitive, and they will be angry if there are consequences to their misbehavior (or angry with a naughty student that is causing them to be punished).