Battery-powered ThermaCELL insoles keep feet warm as outside temperatures drop. The foam inserts have two heat settings, which a wearer chooses via wireless remote. They last up to five hours per charge. ThermaCELL Heated Insoles$130
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.