Fantasy Leagues started in Baseball in USA. They were popularised in Britain & Ireland by David Baddiel & David Skinner in their Channel 4 Comedy Programme, Fantasy Football, during the European Championships of 1996, which England hosted.
They all follow a format whereby players pick a squad from real-life players and are awarded points for how those players do in real life matches (i.e. points are awarded for Goals & Assists in Soccer, as well as points deducted for the defensive players letting in goals.)
As well as numerous online Fantasy Leagues run by the Major League sporting organisations and Big English Sports Leagues, Newspapers run their own Fantasy Competitions ranging from Football to Golf.
Below you will find links to the Results of various Fantasy Leagues in Ireland:
Fantasy American Football Leagues
Fantasy American Football (Decade Overviews):