The upcoming events in the calendar are events that are related to your family tree. You'll see birthdays, anniversaries, etc there.
National and Religious Events are listed in the calendar view only.
The other day I got a notification email for my brother's birthday - it saved me because I completely forgot about it. But the mail reminded me just in time.
My family members requested that the 'Today in history' be replaced by National & Religious events as this is more useful.
In the Administration of calendar settings one can switch the 'Today in history' off, but can not a similar option be put for the National & Religious events?
Email notifications sounds brilliant - I'll definitely switch it on. Does it work for National & Religious holidays too? What about other special days like Valentines, Mother's / Father's day? does the email notification go to only the webmaster or all the members of your site? guys need to be reminded of everything ;-)