If you can accept external solution, Zapier seems to have something - I wouldn't be surprised if others do as well. But just in case: ICS is essentially a some

If you can accept external solution, Zapier seems to have something - I wouldn't be surprised if others do as well. But just in case: ICS is essentially a somewhat standard format for storing calendar entries. If you ever got a calendar event as attachment in file, you probably got it in ICS file (especially common when targeting Apple devices, as ICS is supported by built-in Calendar). So a lot of calendaring etc. software can import ICS, and those that can import over web can be given link that you used to be able to generate from calendar settings in Google Calendar.