Howard Rheingold in the feature about cool heads-up display.

Heads-up displays, first invented for fighter aircraft more than a decade ago, have morphed into "augmented reality" goggles that project an informational overlay over the real world as the goggle-wearer navigates through it. Information about people, places, and things can be seen only by the wearer, displayed automatically or on command. (...) the Information and Navigation Systems Through Augmented Reality (INSTAR) prototype enables the driver to see a transparent arrow floating in space in real time, signaling exactly where to turn en route to the designated destination, or warning of a pedestrian or oncoming bus.