A movement in which the people try to think of various ways to bring that world to an end and then carry it out because thay think the world is so fucked up it can't a fixed and should be brought to an end.
This phrase can be attached to virtually any sentence, as a way to express potentially impending danger for the sake of being accurate.
Student 1: So when do you graduate?
Student 2: 2014...that is, if the world doesn't end in 2012...
Student 1: What gives you that strange idea?
Student 2: Its what the Mayans predicted, and they've been right about a lot of stuff.