Handball may be the strangest Gaelic Game and is not really a big hit with the crowds. A friend of mine once described it as "squash without rackets". He was basically right ...
Handball - Against the Wall
Forget all mental pictures of conventional handball (dubbed "Olympic Handball" in Ireland) - Irish handball used to be played on a court of "sixty by thirty feet" and against a wall, the players hitting a small ball with their hands against this. In the 1920s rules and regulations were drawn up by the Irish Handball Council, part of the GAA.
Popular since the 18th century especially because it required a minimalist outfit (walls were easy to find, so you only needed a ball), this is the one Gaelic Game that actually was widely exported by emigrants. It still is popular in the USA, in Canada, Mexico, Australia and even Spain. The playing field has shrunk, however, and the wall these days is frequently purpose-built with the court covered.
While driving through Ireland you will occasionally see "handball alleys", sometimes looking like disused limekilns, partially torn-down buildings or even shooting ranges. And purpose-built covered courts often lack ground-floor windows, making them a forbidding sight.