NASA has announced that the celestial sphere above us contains not twelve canonical zodiacal constellations, but 13. The heretofore overlooked constellation, Ophiuchus, is purported to guide and command events surrounding humans born between November 29 and December 17.
The addition of Ophiuchus has obvious and far-reaching implications for the entire western Babylonian-derived zodiac calendar. Squeezing it in means changing the effective dates of all the other signs. I used to be a Virgo. I am now a Leo.
update: Apparently this isn't true. (thanks Greg)