1. The body has 12 cranial nerves.
2. A 12 sided polygam is called a dodecagon
3. 12 is a sublime number (yes, that's a real thing-I can't believe you thought I made that up)
It means that it has a perfect number of positive divisors (6): 1,2,3,4,6, and 12 and the sum of these is also a perfect number 1+2+3+4+6+12=28
This is huge because there are only 2 known sublime numbers. The 2nd one is 6086555670238378989670371734243169622657830773351885970528324860512791691264
4. The atomic number of magnesium is 12 in the periodic table.
5. The duodenum is the first 12 inches of the small intestine.
6. The United State is divided into 12 Federal Reserve Districts (can you name them?) and all paper currency has serial numbers beginning with one of twelve different letters, A through L, representing the Federal Reserve Bank where the currency originated.
7. In ancient Greece the 12 Olympians were the principal gods of the pantheon.
8. In Arthurian legend, Arthur subdued 12 rebel princes, won 12 great battles against Saxon invaders, and had 12 knights of the round table.
9. The 12 Tribes of Israel stem from Jacobs's 12 sons and Jesus has 12 apostles.
10. 12 months in a year, 12 zodiac signs, and the basic units of time (60 seconds, 60 minutes, 24 hours) can all be perfectly divided by 12.
11. In both soccer and American football, the number 12 can be a symbolic reference to the fans giving support to the 11 players on the field.
12. 12 Days of Christmas (most people think this is the 12 days before Christmas, but it starts from Christmas day to the eve of Epiphany or January 5)
I wanted to add more, (such as the number of function keys on most PCs, and the 12 Colonies of Kobol from Battlestar Galactica, or the fact that there are 12 basic hues in the color wheel) but then I wouldn't be listing 12, so I didn't.
I think I may have a new favorite number.
I'd love to read your favorite number 12 knowledge in the comments. I'm curious too, how many of you realized it was 12.12.12?
*All this wonderful information (and more) is found on wikipedia here
*Did it drive you nuts that I used 12 instead of twelve? me too, but seeing all those twelve, twelve, twelves everywhere drove me batty too.