The iCalendar specification isn’t fantastic to begin with, and if you dig into the bits about recurring events, it gets even worse. I decided that my calendar application I’m developing needed to support importing from and exporting to iCal format, because that’s what all the other major calendar applications use. When I started looking for an implementation in PHP, I found lots of forum posts asking for the same thing I was looking for, but no complete implementation of the recurring events. So, I decided to write my own… I quickly found out why there aren’t any complete implementations – because the specification is an absolute pain. </rant>