When our teams demonstrate positive behavior, it should be rewarded. It's easy to point out the mistakes - it should be just as easy to highlight the good stuff! For a tactical, visual reward program, why not consider giving Lego pieces as rewards?
How it works: Every time you observe a team member do something well, give them a piece of Lego to keep at their desk. As their good deeds build, so will their stockpile of Legos and they can begin to build.
Side effects: When individuals begin to gather enough pieces to build, their desire to get more pieces to build a bigger item may drive them to do display more positive behavior. And who doesn't love Lego?
Alternative idea: Create a Contest! Make it one that everyone can get involved in - fill a jar full of jelly beans and place it on reception. Let employees guess the answer and give a small prize to the person who guessed the closest.