I have used other Event / Calendar systems and wanted to suggest a couple of nice capabilities to consider:

1)  Ability to configure an Events module as an "aggregate" view for a user.  This unified view would show events from all calendars that the current user has permissions to view. Think group calendars where a user gets a view of all events from groups they are members of.  Have not looked at the schema but this may be relatively easy where the moduleId is omitted from the query.

2)  The ability to manage resources (meeting rooms, projectors) for an event.  An events module moderator would receive requests to approve/deny reservations of 1 or more resources.  During event entry, if a resource was already reserved for a particular date/time, it would show as already reserved and who has already reserved it.