Comment by icebraining

If you want a flexible calendar application that can handle rules like that, you need Remind[1].

For example, if you want to be reminded every third Friday of the month, except on 19th of July because you're on holiday, you can write:

  OMIT 19 July MSG Holiday
  REM Fri 15 SKIP MSG My Event

Now you ask it to print the events for the next six months:

  $ remind -s6 test.rem
  2013/07/19 * * * * Holiday
  2013/08/16 * * * * My Event
  2013/09/20 * * * * My Event
  2013/10/18 * * * * My Event
  2013/11/15 * * * * My Event
  2013/12/20 * * * * My Event

As you see, it skipped "My Event" on the July 19th, because it was an Holiday.

[1]: http://www.roaringpenguin.com/products/remind