I've known of it as "the lying down game" for a couple years now, even had one picture taken (very mild, across raised bits of a reception desk) back when it was all new and exciting and Wow We're Doing A Web 2.0 Thing. Then got bored and moved on.
Planking is a pretty apt name for it to have been given, though maybe not for the more literal woody reasons...
And this fella, well, what can we say. Thousands of people have taken part and NOT chosen to "plank" in an obviously stupidly dangerous and potentially fatal position such as the railing of a 7th storey balcony, and have survived their terrible self-imposed ordeal just fine. One suspects that if he hadn't done this, his genes would have found some other way to remove themselves from the pool instead. Car surfing at 80mph on a road with some low bridges or whatever.