The vOICe - seeing with sound for the blind
The vOICe is a system that takes the input of a camera that is hidden in some eyeglasses and maps that signal into sounds. This is then fed to earphones and is supposed to enable blind people to "hear pictures". Its supposed to actually work - blind people are capable of learning to hear pictures and oriantate themselfes in 3d space with this system. Its like a learned synesthesia (fusion of two or more sensory inputs in the brain). This quite possible means that people are capable of learning synesthesia mappings. Quite mind boggling.
Articles also in the New York Times and BBC News.