By now, you may have heard of the Christian sect that believes that the world is going to enter its final days on May 21 of this year, concluding with the planet's destruction in October.
I could pontificate about this, but really, the best thing you could do between now and then, is to read the classic work on apocalyptic cults and cognitive dissonance, Festinger, Riecken, and Schachter's When Prophecy Fails
(link leads to amazon.com for purchase). It focuses on a flying saucer contactee group in the 1950s (more info at the wiki). The group advertised the end of the world, looking for others to be saved by their space brothers (the one leading them, Sananda from the planet Clarion, also appeared in the past as Jesus according to the group's views). Since it has been written there have been rebuttals and debate regarding the book's key element, the idea of cognitive dissonance. The authors argue that apocalyptic groups invest themselves so much in a falsifiable event (either the world ends, or it doesn't) that when it is falsified, they redouble their efforts and modify their ideology, because admitting their error (often accompanied by public and potentially embarrassing decisions such as quitting a job or leaving a community due to the end of the world) would be too painful. But never minding that, it is easily comparable to the current May 21 group, except that the May 21 group is closer to a much bigger religious tradition, while the followers of Sister Thedra were part of a much more fringe subculture.
The opening of When Prophecy Fails makes it clear exactly how unoriginal such apocalyptic groups are, and how often they follow a similar pattern: once the prophecy fails and the world continues, the group decides that their faith saved the planet, and they launch into a surge of proselytizing. It won't be terribly surprising if we see the same thing here.
