The whole "world ends today" thing, & "the rapture" thing are interesting, because, technically, neither is even in the Bible! Mathew 24:36, Jesus said no one knows the day, or the hour, not even him, only the Father knows when it'll hit, not to mention that Jesus said it'd come like a thief in the night. And in general said that people can only know that it's close by various signs of things that would increase dramatically, but there's no way for anyone to predict a day...or even a year(like say, the whole Mayan calender thing that people are obsessed with). And the rapture just doesn't even appear in the Bible. It's what I'd call an extra-Biblical thing. While there is a scripture that talks about certain one's being caught up in the clouds or something like that, it's not talking about any kind of so called rapture.
It's stuff like this(among many other things) that make other Christian's look nuts IMHO.