Indy Racing League, now the premier racing series, it features cars that are more affordable, and Unlike CART the IRL mainly runs in the United States, with 1 race overseas in Japan. Thus they can have more races as opposed to the expense of transporting cars overseas.
While the term IRL generally means "in real life" in recent years, when combined with LOL the term has grown traction as an abbreviation or shorthand text-speak for "I really laughed". As the phrase 'LOL' -- a term once used to denote actual laughter -- has become overused and utilized in instances where no actual laughter has occurred, IRL is now being used to denote real laughter so as to let the other person know they actually found it funny.