When John Madden, the excitable football announcer, first drew squiggly white lines over a television image during the pre-game of Super Bowl XIV in 1981, he saw the technology as way to level the playing field for viewers.  Instead of needing to explain what he meant by a safety blitz, for example, the Telestrator allowed him to simply draw a couple of x's and o's, a big arrow and exclaim "Heckuva play."

But it's unlikely that he could have foreseen the development of augmented reality, a burgeoning movement as much as it is a combination of technologies. Unlike virtual reality, augmented reality, or AR, takes place in the physical world, except that there's a screen between you and the scene in front of you.  On that screen could be any type of information you wish, from geo-tagged data to real time image analysis.

So what does that actually mean, in our reality? For starters, information about an environment can be mapped onto a live video image in real time. Take, for example, the application Layar, developed by the Dutch company SPRXmobile, which overlays listings (real estate, restaurants, etc.) onto video as you point your device.