Rugby is sport so popular it can almost singlehandedly end the ills of apartheid in South Africa. Ok, so perhaps that is pushing it a little, but the game is exceedingly popular and millions watch the World Cup and arrive with rugby tickets to enjoy the team their fathers and forefathers have been cheering on for decades.
There are two types of rugby, rugby league and rugby union. These two versions of the football game are very similar save a few key differences. First, league has 13 players per side and union has 15 per side. Next, the issue of the tackle is raised. In league, if a team has not scored (by running it in or by kicking it through the uprights) then it surrenders possession. In union, no matter how many tackles occur, a team can retain possession. Thus, unbeknownst to the world outside the UK, rugby has been fighting of a civil war for the past century. More and more sports fans are learning of these differences, as well as the basics of rugby football at the same time. These sports fans would be happy to see either, in a professional or national game. Until then, the two sides can continue to clash, but the union guys would prefer to scrum.