Just heard the most useful suggestion ever, from a friend who says the he heard it on talk radio:
1. At the event, everyone try to interact as many times as possible in a postive manner with the person, not reacting to, but keeping a mental list of, the provocations presented.
2. Within the next week, schedule a dinner with the others at the party (no scheduling at the party). The one with the most postive interactions and ignored provocations gets dinner paid for. The one with the least has to pay the bar tab.