Other Sports - Rugby Variants

Rugby, as a class of sports, is a team game that is alleged to have started when a football (soccer) player became frustrated and picked up the ball with his hands, and ran towards the other team's goal; the other team became incensed at this violation of the rules, and tackled the player. This "history" describes the primary features of Rugby Union Football - the ball is usually carried, and the ball carrier is usually tackled.
The claim that rugby developed from soccer in 1823 at the Rugby School in England is doubtful. Association Football Laws of the Game were not developed until around 1845, so while rugby may have developed from a form of soccer, there was no uniform game of soccer at that time.
It is interesting to note that the original forms of soccer permitted handling and throwing the ball - a player just couldn't run with the ball in his hands. So the idea that Rugby started from a player picking up the ball is unlikely; however, that player running with the ball would have been contrary to the Laws of the Game at that time, and would have resulted in the reported subsequent tackle and brawl.

Rugby Union, the original and dominant form of Rugby, is played in many countries throughout the world. The Rugby World Cup, which is held every four years (next in 2015) included teams from Europe, North and South America, Africa, Asia, and Oceania. ALthough the Americas usually do poorly against the premier teams from Europe, South Africa, and Oceania, Argentina, Canada, and the United States are continually getting stronger, and reaching higher rankings in the IRB (International Rugby Board - Rugby equivalent of FIFA) table. The New Zealand All Blacks have been the dominant team in the sport for many decades, with South Africa, Australia, England, and Wales as continual contenders
Rugby Union (described here) was the original form, with 15 players per team and 40 minutes halves of continuous play.

Rugby League developed in the late 19th century. Rugby League is not nearly as popular as Rugby Union, but is gaining acceptance especially in Great Britain (Super League) and Australia (NRL = National Rugby League)
Rugby League has 13 players per team, and a set of 6 "downs" in which to score, or cause the opponents to commit an infraction which can give them another 6 downs.

Rugby 7s is a small and very fast version of Rugby Union with 7 players per team on a full-sized field.
Rugby 7s is played in 7 minute halves with virtually no stoppage. The 7 minutes of running and tackling is extremely taxing.