I myself have not run the Timewave 2012 program, nor do I claim to know what kind of mathematical formulations it is based on. So I'll start my little tirade by asking this question:
How long does anyone think the present course of human affairs can continue without monumental consequences? To put it another way, how close can you get to the edge of a cliff without falling off?
Some of you on this thread are asking others to 'prove' that the world is going to end in 2012. You want 'evidence,' you say. What you need to understand is that there are things which cannot be proven empirically, yet can be understood innately. I cannot 'prove' - in any definitive way - that I love my parents, but I know that I do, and so do they.
Asking someone to prove that the world is going to end at a given time is like asking someone to give a definite answer to the question, "what came first, the chicken or the egg?" No one here today was alive at that particular evolutionary branch point, so no one here today is qualified to answer that question. All we know today is that chickens lay eggs, which in turn become chickens - or breakfast.
Obviously nobody at present has witnessed the much-prophesied 2012 end/shift/transcendence/nothing, because it hasn't fucking happened yet. You will know 2012 when it comes. If you die before that time, then from your perspective, it will never happen, unless of course you believe that you will continue to exist in the flow of time and witness events from some other-dimensional vantage point (ie. heaven or hell), but that's another discussion altogether.
I believe, but cannot prove, that some sort of larger-than-life, either/or event is going to occur during my lifetime. The threat of runaway climate change, the insanity of never-ending geopolitical conflict, energy disruptions (like the one that turned out most of the lights in LA recently), and developmental progress of benign and malicious technologies all seem to point to something BIG happening in the near future. A revolution of some sort. At some point, humanity IS collectively going to be forced to make a choice: EITHER we will fail to adapt to necessity and die (like the dinosaurs) OR we get our collective 'shit together' and continue the walk down the path of evolution, towards what McKenna called the 'hyperspatial entelechy' - and what I believe is humanity's ultimate reason for being. One way or another, things are going to change, because change is all there is.
John von Neumann said it best:
"the ever accelerating progress of technology and changes in the mode of human life... ...gives the appearance of approaching some essential singularity in the history of the race beyond which human affairs, as we know them, could not continue."