The craziest prediction I've heard so far was that every 3,600 years, a planet called "Niburu" with a highly elliptical orbit flies by us and the gravity rips our planet in half. While at the same time humans are enslaved by an alien race from called the "Annunaki". Which aren't really aliens because apparently they occupied the planet first and engineered us to become their slaves.
Or something along those lines...
Haha, those are some interesting stories. But if the planet is ripped in half every 3600 years, why does it exist today? It should've been ripped in half ages ago...
Never heard of Annunaki; am I a slave of one and just don't know it?
Yeah, so anyway, the Mayans had a circular concept of time. December 21 is the end of the current age, after which time restarts in a sense. I think that last day is written 13.0.0.0.0 or something along those lines.
EDIT: Someone has already said this.
EDIT AGAIN: When I say "the planet", I mean Earth, not Niburu. I misread the post.