Artist Neil Harbisson has a rare congenital defect where he sees no color. Everything is grayscale. But since 2004, he's been hearing colors through a headset with a camera that emits different tones based on the color. It's had a few interesting effects. One, the tones have moved from active knowledge into muscle memory, and the device feels like an extension of his own senses. Two, regular sounds now have a color element to them.
