Pure genius, real future.
Have a look at SixthSense, a MIT media lab project. Here is what a “wearable gestural interface” looks like.
Pranav Mistry, inventor, wearing the markers. Quoting Pattie Maes, “he’s wearing simple marker caps, but if you want a more stylish version you can also paint your nails in different colors” (sorry so candid I had to quote it):
Colored caps are used to recognize gestures:
Data can be projected everywhere for interaction
I mean everywhere
A lot of applications can be written to interact with real world items and augment information on them: 
Some ideas about people recognition already pushing the understatement boundaries: 
Have a look at at the TED presentation by Patti Maes:
Well, waiting for an open-source prototype (as it’s been promised) to play with.
