Teaching the color wheel is fun!
We review in many different ways- including these simple take home bracelets- that only take up the last 10 minutes of a class.
Sometimes we use older clay or Play- Doh that has seen better days to experiment with color blending.
Naturally, kids like paint! But after making our gigantic art math problem, we all get to do hand prints and record them as an answer. They put out both hands and get one primary in each!
Another end of class (extra time project) can be to have kids group colored objects. I put intermediate things in on purpose to stump them- it creates great conversation...and I hope- no fighting!