(1) What Arthur's playing is a game called hurling, an official irish sport. Check out this youtube video:
http://www.youtube.com/watch?v=TmzivRetelE (2) CAO is the Central Application Office, and it's how students apply for university/college courses:
http://homepage.eircom.net/~kennedyr/college/3-form.html (3) Spit is a two player card game, where the object is to get rid of all your cards. Here's a list of the rules:
http://www.pagat.com/patience/spit.html (4) Whist is a card game where people pair up in teams of two facing each other and try to win rounds, or tricks. Here's a full list of rules:
http://www.pagat.com/whist/whist.html