This is the single most important piece of advice ever! Ok not really.
I go to college, I deal with crap like that all the time. If I ever get in a politcal argument and the other person loses his cool I smile real big and say "ok man seeya later take care have a good day" And every time I see him giving me dirty looks, I just smile huge and wave calling his name. Not only is it embarrasing for him, but it makes him look like an idiot. Its all about composure. Just ignore them or kill them sweetly.