I had my first student disagreement today. (Between students not with me!)
I always call them over and serve as mediator. I always have them shake hands in the end and say something like, "Let's be friends" or something. Then I always shock them by saying, "now look them in the eyes and say... OOGA BOOGA.". Up until that point one of them is usually still upset. Then I jump out and make them say it. They always smile and walk off laughing together. MISSION ACCOMPLISHED! :-). I don't even know what made me start doing it. Perhaps I read it somewhere??? Or perhaps it was just a funny mistake that worked out well???
Regardless I've been doing this for years and it makes kids make up quickly! :-).
Do you have any tricks up your sleeves?