The rules of planking, a.k.a. the Lying Down Game, are very simple: lie down face first with your hands by your side and take a picture. Extra points for doing this in a creative location.
Those very simple rules, combined with the ease of participation (just about anyone can lie down on the ground) and the viral capacity of the Internet has turned planking into a verifiable craze.
The Lying Down Game was invented by Gary Clarkson and Christian Langdon in England. They pushed each other to lie down in more and more daring locations and soon, they got their friends involved. The concept exploded beyond their circle of friends in 2007 after a Lying Down Game Facebook group was created. That group now has more than 100,00 members and has been covered by the BBC, the Daily Mail and Sky.