Click the left orange button marked "iCal". This will let you subscribe to this calendar from within your calendar program or app. This is the most likely option for you to use.
Download the iCal feed
Click the right orange button marked "iCal". This will allow you to download a calendar (.ics) file containing the events. This is used by the ZetCal app, but can be used if you do not have a calendar program or app.