Why they prank of course.

Planking, apparently, is the hottest viral craze since flash mobbing.

Planking is the action of lying face down with arms to the sides of the body, in unusual public spaces and photographing it.

That's the definition. The intent, like many fads through the years, is more nebulous.

Within minutes Scott Dixon using his race car as a prop in the Target Chip Ganassi Racing garage at the Indianapolis Motor Speedway for his head-and-toe variation, multiple IZOD IndyCar Series drivers added their own planking photos to social media outlets.