BEGIN:VCALENDAR
PRODID:-//Emacs//NONSGML icalendar.el//EN
VERSION:2.0
BEGIN:VEVENT
SUMMARY:rrule daily with exceptions
DTSTART;VALUE=DATE-TIME:20030919T090000
DTEND;VALUE=DATE-TIME:20030919T113000
RRULE:FREQ=DAILY;INTERVAL=2
EXDATE:20030921,20030925
END:VEVENT
END:VCALENDAR