So I caved and phoned my mum for her ideas on this whole end of the world thingy, since she's read up on Mayan prophecies etc. She finds the whole thing fascinating and did at one point think there was something in this whole 2012 thing.
Basically the Mayans were an ancient race of mesoamericans and very gifted astrologers. They have a few calenders, that are all linked to each other and all follow important astrological and historical events. This whole thing is about their long count calender, when the long count calender ends the 13th Ba'k'tun (I'm not sure about this spelling it is how she texted me it so it might not be Googlable) will end.
People are having a big fuss because it was originally believed that Mayans counted in cycles of 13 and that once the 13th Ba'k'tun ends, that is it. Their cycle is over. The Mayanists (people who study the Mayan culture and calender) believe the cycle simply starts again however recent findings have turned up Mayan calculations and dates that go right past the 17th Ba'k'tun, which is well past our life time and that of our children. A lot of Mayanists believe that the ancient Mayan calculations and calenders actually count well past the life of the sun itself, so we don't need to worry about it (again this theory is backed up by ancient drawings, books and artifacts)
Their calenders are widely believed (and this belief is backed up by findings of ancient drawings and artifacts) to have religious significance. The Mayans believed that humanity was created by five Gods, who wanted to create a race of people in the image of themselves. We, as we are today, are their 13th attempt. Each Ba'k'tun signifies the 'end' of one era of civilisation and the start of another (don't panic at that bit, we are not going to die), at the end of the 13th Ba'k'tun i.e. Friday, a new era will begin. This will be an era of spiritual awareness and awakening. In other words the Mayans think that we will become closer to God-like beings - which seems like a good thing to me, I wouldn't mind being more Goddess like 
Although if you want to believe that you will enter a new Godlike state on Friday, which would be awesome, but sadly implausible, then you should also believe that the five gods once made us out of wood, and although we walked and talked we had no soul, which is why they continued 'improving' us, until we reached our current state (they also tried making us out of clay and mud and things but that wasn't successful either) Evidence of evolution disproves the theory that we were once made of wood and clay.
Their calenders never foretold a chaotic disaster or end of days. Simply an and end of one era and the start of another, similar to our millennium but with a religious background. The Mayan people never predicted planet X or whatever, that was made up by internet trolls, who had no other way to explain what the end of the 13th Ba'k'tun meant, religion isn't as scary to most people as super disasters are, because they are less feasible.
I don't know if any of that will help people who are worried about it, but I hope it will.