At my former job, we had potlucks for just about everything.
We also had a "thank you" board. You could write a thank you for just about anything.(ie: thanks for helping with my patients, thanks for running to pharmacy for me etc.)
Every month, our manager would draw two winners, one who wrote a thank you and one who recieved a thank you, and they would win a gift certificate for the movies, dinner, or to a local retailer. It was a great way to boost staff morale, and the prize was just an "extra" thanks.