It's the year 2023 and you're lost in a gigametropolis full of flying cars and robots who have achieved singularity. A guide literally appears before your eyes, giving you enough info about your surroundings to guide you on your way. The computerized contact lenses that Babak Parviz is developing could make this fantasy a reality.
Parviz is working on a contact lens that can give visual feedback to the wearer using an embedded CPU. It can also glean data from the wearer's eyes and transmit that data somewhere else. While the current prototype is rudimentary (read: an 8x8 pixel LED array), Parviz says you don't need terribly complex tech to create an augmented reality interface, and thinks that with the help of laser imaging, he can create a sharp enough interface to overlay on the eye.
As for a power source for the mighty little lens, Parviz is working on solar or RF power harvesting to keep the contact lens going.