Birthdays and actual events should be listed seperately on the calendar. Events are more important, but there's a lot of birthdays. It's impossible now to discernate between them. If a real event is planned, that should be made VERY clear.
There should be the possibility of making a calendar event span a number of days, instead of just one.
Moderators and admins should have the possibility to NOT display the 'edited by...' text on edited posts.