Google Calendar - Traditional post

webcal://www.skysports.com/calendars/football/fixtures/teams/barnsley?live=false

Go to your Calendar
Other Calendars + (Bottom left). Click the +
Click From URL
enter webcal://www.skysports.com/calendars/football/fixtures/teams/barnsley?live=false
Click Add Calendar
Bob is your uncle.

From 2017 debate at
http://barnsleyfc.org.uk/threads/do-this-to-add-fixtures-to-google-calendar.256676/

I don't know if the Barnsley one still works, I'm sure Whitey will tell us if it does.