Great visual whole-class incentive...you can adjust the size of the brownies to make incentives easier or more challenging to earn. You don't have to reward them with actual brownies--let the class suggest incentives they're motivated to earn!
Classroom reward system- If the class shows great behavior, they will get to color in a letter tile of their choice. When every tile is colored in, the students will win that specific award. I just googled "Scrabble Font" and downloaded it for free. :)