http://fluid.media.mit.edu/projects/eyering

"EyeRing is a wearable interface that allows using a pointing gesture or touching to access digital information about objects and the world. The idea of a micro camera worn as a ring on the index finger started as an experimental assistive technology for visually impaired persons, however soon enough we realized the potential for assistive interaction throughout the usability spectrum to children and visually-able adults as well."

Being able to point to things and instantly receive information about them without having to ask someone or Google it is a phenomenal interaction. It not only cuts the overall time to access the information, but also makes it more accessible and frees up the user to interact with any physical object with less confusion. Knowledge at your fingertips is quite literal in this scenario.

Similarly useful and intriguing: the FingerReader

http://fluid.media.mit.edu/projects/fingerreader

"The FingerReader is a wearable device that assists in reading printed text. It is a tool both for visually impaired people that require help with accessing printed text, as well as an aid for language translation. Wearers scan a text line with their finger and receive an audio feedback of the words and a haptic feedback of the layout: start and end of line, new line, and other cues. The FingerReader algorithm knows to detect and give feedback when the user veers away from the baseline of the text, and helps them maintain a straight scanning motion within the line."