It was asked at the Tech Leaders meeting last night if it was possible to transfer a shared calendar (building events and so on) from one staff member to another - should that staff member leave the district.
According to the Google Support Site, you sure can!
To transfer an individual calendar between two Google Calendar products, simply share the calendar with the new owner. Be sure to select "Make changes and manage sharing" in the permission level drop-down to effectively transfer ownership of the calendar.
While it's not possible to merge two Google Calendar products at this time, you can use this tip to transfer your calendars to your preferred Google Calendar and discontinue use of your other Google Calendar.