According to wikipedia.org, Friday the 13th happens at least once, but no more than 3 times a year. And that is because when a month begins on a Sunday, then you can expect the 13th to fall on a Friday. This has already happened this year (3 times) for the months of February and March, and now November. You won't see it happen 3 times again till the year 2012.
Also, according to folklorists, there is no written evidence for a "Friday the 13th" superstition before the 19th century. The earliest known documented reference in English occurs in an 1869 biography of Gioachino Rossini: Rossini was surrounded to the last by admiring and affectionate friends; and if it be true that, like so many other Italians, he regarded Friday as an unlucky day, and thirteen as an unlucky number, it is remarkable that on Friday, the 13th of November, he died. Spooky!
To me, Friday the 13th is just like another day, but for some reason, it always seems to be a good day for me. Sometimes I even have some good luck, like the $50 check I received in the mail today from Twolia.com. WOOT!! I love that kind of good luck! ;) If you want to see more of my jewelry, you can check out my shop on Twolia here. Whatever Friday the 13th means to you, if it means anything at all, I hope you have a happy day! Now...to dig out some of my scary movies for tonight! :O