Harbisson was born color blind, but he found a computer scientist, attached a camera to his head, and attached it to a chip in his skull. Now, the chip emits sounds based on the colors in the camera, and his brain can interpret the sounds as colors. He decided that he wanted more than the visible spectrum, so he added on infrared and ultraviolet.
He talked about a lot of the ways that hearing color has changed his perspective. Someone might have an ugly face that sounds beautiful. He stopped coordinating his dress based on color and started coordinating it based on sound.
It will get really cool when we get better at giving people senses that never existed in the first place, though. Like a chip in my brain that tells me how many unread emails I have.