Hike at night—or find your way to the outhouse—with the strongest headlamp yet. Its six LEDs yield 350 lumens, which shine about 400 feet. Petzl designed circuitry that ekes the most power out of the rechargeable lithium-ion battery, letting the 12.2-ounce lamp burn on its highest setting for two hours. Petzl Ultra Headlamp $425; petzl.com
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.