U.S. open-wheel racing's biggest race, the Indianapolis 500, revs up for the 97th time from Indianapolis Motor Speedway with the traditional "Gentlemen, start your engines." Answering the call on the 2.5-mile oval will be the likes of Ryan Hunter-Reay, James Hinchcliffe, Helio Castroneves, Scott Dixon and 2012 champion Dario Franchitti.