What big event will happen in 2012

Like Tsunami hurricane earthquake

Obama losing

> Like Tsunami hurricane earthquake

None of these are astronomical events and none can be predicted with any accuracy in advance.

Since you are asking in the Astronomy & Space category, here is a list of astronomical events which are predicted to happen in 2012:

Mars opposition: March 3
Mercury eastern elongation: March 5
Venus eastern elongation: March 25
Saturn opposition: April 15
Mercury western elongation: April 18
Annular eclipse of the Sun: May 20
Partial lunar eclipse: June 4
Venus transit: June 6
Mercury eastern elongation: June 30
Venus western elongation: August 14
Mercury western elongation: August 16
Neptune opposition: August 24
Uranus opposition: September 29
Mercury eastern elongation: October 26
Total eclipse of the Sun: Nov 13
Jupiter opposition: December 2
Mercury western elongation: December 12

Of these, the most interesting for me are the transit of Venus on June 6 and the solar eclipse in Australia on November 13. The transit, because I really enjoyed observing the previous transit in 2004, which was at sunrise, and would like to observe another of these "once in a lifetime" events; this one is at sunset. The eclipse, because it's the next one, and I hope to have had a kidney transplant by then so that I can attend.

There are over 30 earthquakes a DAY (most of them are minor), so take your pick. We should expect a hundred "good" ones and a good dozen big enough to make CNN.

There are roughly 100 hurricanes a year (if you count them on all oceans, under different names like typhoons)

There will be a transit of Venus (Venus passing in front of the Sun's disk) just like it did in June 2004.

Morons will say the world will end in 2013 when December 22, 2012 comes around.