Dan Koeppel

Brett Sharenow is presiding over the Pepsi Challenge of lightbulbs. The CFO of Switch, a Silicon Valley startup, Sharenow has set himself up in a 20-by-20 booth at the back of the Pennsylvania Convention Center in Philadelphia, and he’s asking passersby to check out two identical white shades. Behind one hides a standard incandescent bulb, the familiar lighting technology that has gone largely unchanged since Thomas Edison invented it 132 years ago. Behind the other is a stunning, almost art- deco-style prototype that holds 10 LEDs and a secret fluid. It’s a liquid-cooled bulb, as radically different from Edison’s invention as anything that’s ever been screwed into a standard socket and, Sharenow hopes, the next big thing in the $30 billion lighting industry. The challenge: Can you tell which is which?

You’re six miles up, alone and falling without a parachute. Though the odds are long, a small number of people have found themselves in similar situations—and lived to tell the tale.