Not a darn thing.
Actually, I do believe that global climate change and oil scarcity will together lead to a decline in what is generally called industrial civilization, and that this decline will along the way be marked by a variety of disasters and catastrophes and situations. But I don't believe 2012 has anything to do with it.
We don't believe in the end of the world in a spiritual sense. Our religious beliefs don't include an apocalypse or anything like that. Someday our star the sun will grow old and die. There will be major earthquakes, meteors that hit the earth, and similar natural episodes, and these will have a serious impact on the way life on earth evolves. But the "end of the world" as an act of a deity is foreign to us.
The Maya had a very advanced understanding of astronomy, and kept a very accurate calendar, but I don't believe they had any kind of special knowledge about the spiritual or material destiny of humankind.
So no, I don't think anything special will happen that year. Well, my twins will start start kindergarten, and that's pretty special to us.