To add the St Carlo Calendar to your own ical (Apple) or google calendar, copy and paste the following address into your calendar where you "add other calendars"
http://www.google.com/calendar/ical/aql5iba64ol0vsuvm8lbpehilo%40group.calendar.google.com/public/basic.ics
Alternatively, you can view the school calendar in Audiri under Events.