I've been pretty obsessed with this test for the past 24 hours. It quantifies your ability to discriminate between different shades of color. I know I have color blindness tendencies (on color blindness tests I can sometimes see the answers for normally-sighted and color blind people). The test also shows you which hues give you the most trouble.
I got an 11 the first time and a 4 the second on different computers (the lower your score the better). I think your monitor can make a difference. My husband got a perfect score (and for the record he looked over my guesses the time I got a 4 and didn't see how he'd change them). My red-green color blind mom got an 83.