Curious about how well you see colour? No matter how you spell it - color or colour - I think you will enjoy these fun, but challenging links. Start with this easier colour challenge from RIF (Reading is Fundamental) to warm yourself up!
I found this color test from Xrite (a global leader in color science & technology) particularly interesting . Allow yourself some time.
From Method of Action (upcoming site for peer to peer education for people who want to get things done design wise). This also works on an iPad. And, don't worry! You are not alone if you find you find the "Triadic" & "Tetradic" tests more physically challenging than the color test itself. (You'll see, she says smiling) .