Headset Uses Bone-Conduction Technology
Wired reports that a new headset is on the way to solve all those background noise problems you have had with your cell phone in crowded areas. This new bluetooth headset uses "bone-conduction" technology that converts vibrations from you jaw into sound. The article claims it should be available as early as later this year for around $200.
Bone microphone technology has been around for quite some time in the two-way radio communications biz, and it's much more discreet.
Bone microphones are sometimes used in the movie industry to communicate with actors/stunt people while on camera, when the person is too far away to reliably hear direction (if the person is dangling from a construction crane, for example).