A ruffian's game played by gentlemen.
Rugby is a fast, skilled, team-oriented game combining the tactical complexity and physical brutality of American football (only without the padding) with the continuity and pace of soccer and the scoring rate of lacrosse.
Unlike many other sports, rugby has succeeded in maintaining as part of its culture respect for both the opponents and the referee. Players are seldom heard to argue with the ref and after the game, both teams and the ref can usually be found drinking and socialising together in the clubhouse.
There are two distinct types of rugby: union and league. They play to separate systems of rules and both have their merits. The split dates back to 1895 when the game was unified and amateur. The sport's governing body (the RFU) refused to allow a number of clubs in the North of England to pay their players (many of whom were miners) for time lost from work in their services to the club. The RFU even threatened to ban the players for life if they were found to have been paid - they saw professionalism as an evil threat to the values of the game (read: the big, poor, burly miners would beat up the rich wimps if they played on a level footing). So the Northern clubs seceded from the Rugby Football Union to form the Rugby Football League and made rules changes to speed the game up.
League is a simpler, faster game than Union. The pitch is the same size as Union, but teams consist of only 13 players, so there is effectively more space. Contest for the ball at the tackle is not permitted - instead a team has only 6 tackles worth of possession before the ball is turned over (a bit like downs in American football, but without stopping after every play). This leads to the tactic of teams kicking the ball upfield after their 5th tackle in order to give their opponents as poor a field position as possible.
Union is a much more complicated game than League. Contest for the ball is permitted and encouraged at every phase of play - tackle, scrum, ruck, maul, line-out, the lot - leading to a greater number of turnovers and hence a more fluid game. There are 15 men on a Union team, so space is more limited, meaning there is less opportunity for individual brilliance and a greater reliance on the team to function as a unit, and consequently more obvious player specialisation.
Personally, I prefer Union, bubt they're both good games.
The rugby team's looking good for promotion this year...