Rugby is a sport played by 15 players on each team. To stop the other team you tackle them. You can only pass backwards. There are two posts one at each end of the pitch. The players are trying to score by touch ing the ball down on the other teams try line this is called a try. This gets you 5 points. After a try you are given a conversion which allows you to get 2 more points (only if your kicker gets it over the post though)
Scrums are given when the ball is "knocked on" this means that a player hit the ball forward with his hand and didn't catch it before it hit the ground. They are also given when there is a forward pass.
Lineouts are given when a team knocks the ball into touch (touch is the line that goes along the side of the pitch). The hooker throws the ball down the middle of the both teams. The players are trying to jump up and knock the ball back on their side.
rooks happen when a player is tackled with the ball and both teams try and get the ball back this usually results in a pile up.
Mauls happen when a player remains standing while people on both teams try and pull it back on their side.
Penalties are given for anything you do that is dangerous to another player, such as tackling around someone's throat. This is just an example there hundreds more but purposely knocking down a scrum or a maul is another.
Red cards: red cards mean that you are off for the entire game
Yellow cards: yellow cards mean that you are off for 15 minutes