Suggestion: Tagging/label support for calendar events.

[Aaron Mitchell]

It would be really helpful to have the ability to tag/label calendar
events and to query for information on those tags.

For instance, if I were a consultant providing technical training for
multiple clients, it would be nice to be able to gather statistics on
how many hours of each technology I had presented, or how many hours I
had presented for specific companies. Since each event would need to
be classified with multiple labels (i.e. company, technology, etc.)
this functionality can not be accomplished by using individual
calendars.