Man, where to begin? I usually try to go for a drive... you know, just get away from the situation before I do or say something that I'd regret. But that doesn't really answer the question, does it?
I think to avoid anger completely, you really have to pick and choose your situations. Get control before an issue even arises, and definitely grow some thick skin. One thing I have noticed is how angry people can get behind the wheel... my wife, especially. She'll get so mad at someone, even if they did not do anything intentionally.