We worked on colors a little bit last week. Little Boy knows the names of the colors already, so we went a little bit beyond that and learned about mixing colors.
I have some food coloring in little jars that my mom gave me awhile ago--the ghostly white things floating in the bowl up there are toothpicks that we used to scoop the color out of the jars. We put red, yellow, and blue in bowls of water, and then mixed colors in the cups.
I'm not sure Little Boy really "gets" it yet. He doesn't remember now which primary colors to mix to get each secondary color. But at least he understands that colors can be mixed to make new colors.