The World Series is the championship games of Major League Baseball in North America, played in October after the end of the regular season between the winners of the American and National Leagues. There is a best of seven playoff, meaning the first team to win 4 games wins the series. This has been an annual event since 1903. Baseball is so popular in the US that sometimes it is called the “national pastime”. The rules of baseball can be found at http://aupairinameric.com/resource/life_in_the_us/baseball.asp.