Ask HN: What do you use for Calendaring?

I am looking for a provider for calendaring, preferably with caldav. I don't use google products other than basic android without google services. I don't own any iDevices either. I use fastmail for email but don't use email on phone and don't want access to email to be on phone and fastmail provides no way to differentiate access.

Are there any other providers you could recommend or think are great even if they don't meet my requirements.