Unlucky for the Superstitious

My computer programming brother informed me that the 13th day of the month occurs on Fridays more often than on any other day of the week (he wrote a program to find out).

Are there any Friday the 13th bad luck book stories out there? For a few moments this morning, I entertained the creepy horror of receiving a rejection on this Friday the 12+1. Luckily, I ate enough garlic earlier in the week to suppress any further superstition.