To export your Apple Calendar to an ICAL file, load up your calendar. If you don't see a list of calendars on the left, click the "Calendar" button at the top. Then click on the calendar you want to export.
Next, click on "File" up in the menu bar, go to "Export" then click "Export..."
It will ask where you want to save the file. Save it to your Desktop. Then email that file to us at firstname.lastname@example.org.