I found this activity on the Pinterest boards at Your Therapy Source.   It was pinned to Pinterest by Tot School Tumblr, and seems to have originated on The Clark Family blog, although I cannot find the original post.

From Tot School Tumblr:  I made this really cool game that they LOVED doing! I used sharpies to color the clothespins and turned pipe cleaners into a loop. They then matched the correct color loop and pinned on the clothespin. Not only do they think about the colors, but use fine motor skills too! They each got one bag with a set of colors each: (via The Clark Family