Proof that humanity has sunk to its lowest point in history thus far. It is the act of lying completely flat across pretty much anything in an urban setting. A friend will take pictures of the act and, of course, post them on Facebook or Twitter. Much favored by hipsters, douchebags, and the like. This trend is currently sweeping the internet, reason: unknown.
Proof that literally ANYTHING can catch on if enough idiots think it is "cool".
Hipster 1: "Hey guy, I just took some awesome planking photos at the Starbucks downtown!"
Hipster 2: "DUDE! I was planking on some benches at the quad yesterday!"