What is ical?
Ical provides an X interface for maintaining a calendar. A calendar is
basically just a set of items. An item is either an appointment, or a
notice. An appointment starts at a particular time of the day, and
finishes at a particular time of the day. A notice does not have any
starting or ending time. Notices are useful for marking certain days as
special. For example, a calendar may contain a notice for April 15th
indicating that taxes are due. When the documentation below refers to an
item, it applies both to notices and appointments. The main features of
ical are: