Tackles are one of the main ways to gain the ball from an opponent in a game. Tackles can be done in many ways, and can look really cool and effective.
Rugby is a team game where one team is aiming to get the ball to the try line on the other side of there opponant. Many believe that rugby was born in 1823 when William Webb Ellis "with fine disregard for the rules of football (note that football was yet to split into the various codes) as played in his time at Rugby school, first took the ball in his arms and ran with it, and Rugby was born!