I think its so odd that this 2012 thing has gained so much saport even in the media. WE called those people crazy for thinking that there was a space ship on the tail end of Hale Bopp.
Buying into these dooms day predictions can be very dangerous. That teacher telling kids not to bother is hurting their potential academic future not to mention their sense of security. The Millerites gave away their possession and didn't plant crops believing the world would end April 23, 1843. It must have been hard waking up April 24th to realize you had nothing left and no food to feed your family through the winter for some of them it WAS the end. And finally the people from Heaven's gate committed suicide so maybe they where right. Their world ended.
There have been many doomsday predictions many of them recent. Here are some interesting links to failed doomsdays.
doomsdays1
doomsdays 2
doomsdays 3
If any of these cults sound crazy remember people believe in them. Belief makes anything make sense.