Neil Harbisson is an artist who was born with a rare form of colorblindness called achromatopsia -- he sees everything in grayscale. The typical "colorblindness" we talk about is more of a color confusion in which some colors blend with others, or it's hard to distinguish between certain similar colors. So Harbisson's condition is unusual to start with. What makes it rad is that he wears an "eyeborg," an assistive device that reads colors in front of his face and plays musical tones in his ear. This technology gives him a way to experience color, and after many years of using the device full-time, it has become like a native sense to him. He also uses it in his art, and he shows some examples in this talk. He has even extended the device to go beyond the typical human visual color spectrum, so now he perceives infrared and ultraviolet.
Harbisson is one of a growing group of cyborgs. (Amber Case is another.) What's it like being a cyborg? Apparently pretty cool. Here's a brief, fun TED Talk in which Harbisson explains the situation:
And here's a Discovery clip about Harbisson from 2007, with a bit more detail about the eyeborg and its development:
Finally, Harbisson has an extensive Wikipedia page, including detailed explanations of the eyeborg and his Cyborg Foundation. Well worth a look if you're interested in the specifics of how the system works, and/or want to become a cyborg.
Also relevant is DanKam, a smartphone app that helps colorblind people discern colors. DanKam has helped me lots of times -- I don't see dark greens well, so I use DanKam to pump up the visual volume.