Graphics professionals have been doing it for years. I'm referring, of course, to calibrating displays to achieve accurate color rendition. Pros use hardware-based calibration systems that not only ensure accurate color reproduction, but can also perform the calibration process quickly.
Screen shot courtesy of Coyote Moon, Inc.
But you don't have to be a graphics pro to need accurate color. If you have digital photos, getting them to look their best starts with the knowledge that what you see on your monitor matches the colors captured by your camera.
You don't have to spend your hard-earned cash on a color calibrator to get accurate color. With a little free time and a bit of fiddling, you can calibrate your monitor using the Mac's built-in display calibration assistant. Get comfy and take a look at: