Picking your favorite non-lethal weapon can be tough. I'm partial to the microwave-based Active Denial System that former PopSci editor Eric Adams had the, er, courage to stand in front of a few years ago. (An experience described in detail here.) Or I might give a nod to the paralyzing, hardening foam that momentarily holds down The Hulk in the 2003 movie, and has been used by the U.S. military with mixed results.

But a California company may be developing the real winner, an LED-based flashlight that shoots out incredibly bright pulses of light, and can potentially induce vomiting. The Department of Homeland Security is funding the study, and Penn State will begin testing it this fall at the Institute of Nonlethal Defense Technology. Any volunteers?—Gregory Mone

Since the bombing of the U.S.S. Cole in 2000, protecting docked ships-both military and commercial-has been a big priority in the fight against terrorism. The Department of Homeland Security has already awarded $489 million to help guard the nation´s ports, spurring a number of innovative ideas, the latest of which is an underwater system that blasts enemy swimmers with painful acoustic waves. Patented by the Raytheon Corporation last October, the system is the brainchild of former Navy and Raytheon acoustics expert Frederick Di Napoli. His scheme is simple: Generate a region of high-pressure, low-frequency sound around the ship, creating a sort of sonic fence that â€shocks†anything that swims through it. Although a diver would probably flee from pain, Di Napoli says, "you could really dial up the pressure and make it lethal if you had to."