I Spy

This is a game you can play that helps children identify colors.
Choose something in the room and note what color it is. Say, "I spy with my little eye...something green!" (or whatever color it is). The children take turns guessing what you picked. Whoever guesses correctly can then take a turn being the "I spy" person.
With little children, you can put a few obviously colorful things on display (stuffed animals, blocks, etc.) and play with just those things. With older children, you can pick random small things to make it harder.