I have just read that the world is supposed to end (again!) on 20 December, 2012, because of 12/12/12, also because the Mayan calendar ends that day, though why the Mayans should control the world is not clear (plenty of Google links but a bit far out for me to quote!).
If this theory holds water then surely the world should have ended in on 12 December 1212, 12/12/1212?
Or why not the last 12/12/12 in 1912, or 1812 and so on?
I can just imagine what happened in that ancient Mayan civilisation, which has resulted in all these end of days theories:
Imagine 3000 years ago in the middle of the Mayan age. 2 poor sods have been tasked with producing a calender for the civilisation and have been sat in the same room for weeks on end repetitively counting and writing days. Eventually they ran out of anything to write on and instead of going to the local purveyor of parchment to carry on, they said "you know what? We've done 3 thousand beedin' years on this calender. Let us go and get drunk".
Hence the calender stopped on (when translated into 'modern' timing) December 12th 2012.
Well, my theory is full of holes, but I prefer it to the one that says they foretold the end of the world!