Each Labor Day weekend, NHRA racers and fans descend on O’Reilly Raceway Park at Indianapolis for the biggest, oldest, richest, and most ­prestigious drag race in the world. The fabled quarter-mile is regarded by many as one of the smoothest on the circuit. The marathon also hosts two high-dollar bonus events, the $100,000-to-win NHRA U.S. Smokeless Showdown for Funny Cars and the Ringers Gloves Pro Bike Battle, which pays $25,000 to the winning Pro Stock Motorcycle rider.