For an article about what happend 5200 years ago in a scientifical paper completely unrelated to the mayans and 2012 myth, check this article:
And in this article the scientists say that we are close to another change like that which happened 5200 years ago... Again it matches perfectly with the mayan prophecies. So, we should take the knowledge of the mayans quite serious in my opinion. they knew what they were doing and thats a fact.
Also remember the great floods, past ice ages etc, that fits well with the mayans cycles. Look them up, they have various cycles of different importance, going through many thousands of years. Actually they have cycles going millions of year back.
We just need to look at the current state of the world to see something is cooking (literally) - global warming, ice caps melting (which can cause floods etc), war, terror and instability, increase of natural disasters, magnetic poles of earth shifting and so on.