This page lists the basic colors in Spanish and the words are colored to match. Give the students each a pack of crayons and have them get out the colors on the list. When you say each color hold up your crayon of that same color, and have them mimic you with their own crayons. Repeat this a few times until the students no longer hesitate when you call out a color.
Colors include: red, blue, light blue, dark blue, yellow, orange, green, purple, white, rainbow, black, grey, brown, and pink.