A "Friday the Thirteenths" Solution
There was a recent post on LessThanDot to create a small application to find all the "Friday the 13th's" occuring in a range of dates. Here is my simple solution to the challenge. I also made it flexible enought to find any occurrence of a day / day of week combination within that range. It runs surprisingly quick even when looking over the next 500 years.

Also, if you like my color scheme, I've made it available for download here.