Next time you pass a state trooper, mark the spot on this radar detector. A GPS chip inside alerts you when you near the area again. Flag chronic false-alert locales, and stray beeps disappear. Escort Passport 9500i $450; www.escortradar.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.