Vampire LARPs, although I did do monstering for a weekend long fantasy LARP once.
I have to say that it was much easier to get the right ambience in the St Andrews Scotland LARP with its ruined castle and cathedral and other old buildings and long dark nights than it is in sunny sydney lol
I have never done a LARP before. It might be fun but then again every person that I have ever know that does LARP was 1 step away from being certifiable.