What will happen on December 21st 2012.... Nothing
What will happen on December 23rd 2012.... Nothing

What will happen in 2013? probably something, I mean, it's a whole year.

....and after that the world will slowly decay as it did for the past 40-50 years, at an alarming rate.

We will(In a Panic) spend all our money building shelters and buying non-perishable foods. The amount of work needed for this job will cause construction workers and grocers alike to die from exhaustion(of course some people might die from getting trampled in the stampedes to get the food). All of savings will go into protecting ourselves from the apocalypses. When the day hits and no natural disasters happen people will feel as dumb as they did back in 2000, only this time, what they didn't realize is they created there own hell. They put themselves and companies into debt. There will be no jobs, no laborers(they died before this day happened) and everyone will be sad...except for the shelter and can goods industry they made millions and now the big "green giant" is the new world leader.

Something really bad will happen! Massive natural disaster or another war will break out, something extremely bad that will treaten human life, it wont end just end as we know it today!!

you forgot to add "nuclear war"

The world will end because Sarah Palin will be inaugurated as the 45th POTUS.