What is 2012 mayan calendar ?

On the internet many times i see these words mayan calender,2012 mayan,mayan prediction.Any body help me to find the Truth of these words.

The Mayan Long Count calendar clicks over from 12.19.19.17.19 to 13.0.0.0.0 on 21st December 2012. That’s all there is to it. It’s the same as our calendar changing from 1999 to 2000. The Mayans themselves never predicted the end of the world would happen at that time.
All the doomsday predictions attached to this date are, without exception, unscientific nonsense, perpetrated by frauds and hoaxers.