X-Rite and Pantone came together to make The Color Test, a free, online color-perception test. It takes around five minutes and can be challenging, but offers insight well past if you’re simply color blind or not. You’re graded out of 100 and shown where (and to what extent) your color problem areas are.
Fair warning: for those working in, or with, designers, the competition as you pass this around the office can get a little fierce. Let us know your scores!