Public URL to Calendar
https://calendar.google.com/calendar/embed?src=c_5bbd99b6d2669077c60b8067264cb0448a035d799d7c366b9cc11e5f378459bb%40group.calendar.google.com&ctz=America%2FVancouver
Public address in iCal format
https://calendar.google.com/calendar/ical/c_5bbd99b6d2669077c60b8067264cb0448a035d799d7c366b9cc11e5f378459bb%40group.calendar.google.com/public/basic.ics