We'd like to add to Calendar the ability to support external Calendar sources. Ideally this would both read and write both ways. So if I create an event in Phabricator, it would update my Google Calendar and vise versa. The overall goal is many small companies use Google to manage their work calendar, and that information automatically synced to Phabricator is handy.
For this task you will need a Google account if you do not have one::
You will then need to register with Google APIs:
Go to Services in API Project and turn on Calendar API.
Getting started on implementation:
Google provides both a REST API and PHP Client Library
@epriestley to confirm which approach.