The Six Nations rugby championship is kicking off and over the next few weeks you're probably going to be hearing about it a lot.
But if you don't know the first thing about rugby then fear no more!
Check out this guide to find out all you need to know about the Six Nations, and the sport of Rugby Union, before the tournament starts on 3 February.
Rugby Union is played by teams of 15 players, with each team made up of eight forwards and seven backs.
The forwards are generally bigger and heavier and the backs are faster and smaller.
Even at the top level it used to be amateur - that is, played for fun by people who had other jobs too - but now the top players are all professionals.
The biggest competition in Union is the World Cup, played every four years, but the most famous one in this country is the Six Nations championship.
The Six Nations is a rugby union tournament played every year between the top countries in Europe.
The six countries who take part are England, Scotland, Wales, Ireland, France and Italy.
For the first 90 years of the championships there were only five countries involved, but Italy were invited to take part in 2000.
If a team wins all five of its matches it is called a Grand Slam, but to win a Grand Slam is very hard.
England won a Grand Slam in in 2016.
The Triple Crown is a special prize that only the four home unions - England, Scotland, Wales and Ireland - are able to win.
A team can only win the triple crown if they beat all three of the other home sides.
The sport gets its name from the place where it was invented, Rugby School in Warwickshire, England.
In 1816 a pupil called William Webb Ellis got a bit bored during a match of football and decided that picking up the ball would make things more interesting.
Although the game has come a long way since, even splitting into two codes; Rugby Union and Rugby League, that's where it started.
One of the most important rules of the sport is that the ball can only be passed backwards.