Apparently in ancient times thirteen was regarded as a truly auspicious number. It's linked to lunar and goddess worship and represents luckiness, fertility, potency and good fortune. Oddly enough the Moon does have roughly thirteen revolutions around the earth in one year in addition to thirteen annual cycles.
Ultimately, it's just another day but here at SM, Hq we're running studies in Aural Quantum Manifestation. So we suggest turning up the music and rocking out on this planetary spaceship called Earth and remember... T.G.I.F