There is an interesting potential for federated wiki to facilitate calendar coordination around finding a mutually convenient time to meet with others. Lots of people will have a calendar application that they use and most of these apps will allow them to either download or link to a public *.ics file on the web. This is using the iCalendar standard as described here on Wikipedia 
We will preview the contents of these ics files to see if we can incrementally make sense of them. github
See also Calendar From Links
Below are two ics files, one which should have just 2 singular events on it, and another with a single recurring event.
pages/calendar-coordination
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Read about our Quest for Beauty in iCal Records