Take the Test: How Well Do You See Color?
It is generally believed that around 1 out of 255 women and 1 out of 12 men may have some degree of color blindness. When you consider the importance color plays in the products we buy, our aesthetic tastes, and the design decisions we make when we decorate, it's quite intriguing to consider that many of us may not perceive colors in the same way.
X-Rite, a company that specializes in the technology and science of color (and who also owns the popular color system Pantone) offers a really interesting tool to test your "color IQ" online.
A series of subtly varied color swatches ranging between two hues is presented out of order, and it's up to you to rearrange the swatches so that the gradient between the two colors is correct.
Take the test here: http://www.xrite.com/custom_page.aspx?pageid=77&lang=en