Our FC uses Google Calendar. That way they can import it onto their phones if they like.

I also created in a way that allows any user to add their own events through a Google Form submission to a Google Spreadsheet that then adds it the FC calendar. This way non-Google users can use the calendar as well. And it allows me to keep the calendar's permissions locked down to prevent public/anonymous events from being posted.

But yeah if they add a calendar feature in the game that would be awesome, along with permissions for adding/editing/removing events. And for a bonus allow us to access it through either Lodestone or other media devices such as our phones (via standard file formats .ics or .csv.)