Personal events are events that you can add to your calendar for any reason, they will be visible only to yourself.
Coven events can be added or edited by Council or Priest/ess of covens (except the Spellcasters Coven who can not add events). These events will be visible to all members of that coven.
Global events are added by the website and are limited to a handful of Pagan celebrated days.
Local events will be added in the near future when local groups are added to the site.
Finally birthdays are also shown. For a birthday to appear in your calendar, the member must have added you as a friend and set their birthday information to public in their edit profile page.