It’s pi-day pips March 14th, 2009
The first reference to pi came in 2000 b.f.c. from the Babylons, their value was 3.125. The value of pi has become more and more accurate over the years, and many major cultures have been involved. The latest big breakthrough came from the distributed computing project PiHex who computed the 1,000,000,000,000,000:th bit of pi, which turned out to be 0.
For more info, check out piday.org and the wikipedia article on pi