I used to worry about it, but then I looked further into it, more than just what they put on tv. The Mayan calander is split up into different ages, according to planetary alignments. We (the human race) has already survived at least 4 of the ends of these ages.
It predicts the end of the world AS WE KNOW IT. For all we know that could mean that the sky will turn pink with green polka dots!
Don't be too concerned about it. I remember, when I was about 14 some mystical-type person who had successfully predicted both world wars, the hindenburg disaster and loads of other events had predicted the end of the world at mid-day on this date. All the girls in my class were counting down the seconds and when the world didn't end it was sooooooo anticlimatic!!!