To get drinkers to play it safe after a night out, three young entrepreneurs are banking on a police-grade breathalyzer that they call Alcohoot. The $99 device plugs into an iPhone and communicates with an app. After a gusty blow it logs and displays your blood alcohol content to within a hundredth of a percent. If you're above the legal limit, it helps you search for the nearest greasy spoon -- or a cab.
Alcohoot's founders gave us a demo on the floor of the New York Stock Exchange during the 2013 Kairos Global Summit recently. (Don't worry, boss -- no one blew above 0.00 percent.)
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.