I found this really cool painting idea on Artful Parent. She used liquid watercolors, we opted for the what's in the cupboard "paint". Using food coloring, water, squirt bottles and pillowcases, we learned that red + blue = purple, yellow + red = orange and blue + yellow = green. Learning really can be fun.
The boys kept squirting water on their pillowcases after all the "paint" was gone so none of the color stayed, but they had a blast and stayed cool. Bonus - we get to do this again with the same pillowcases! Woot woot! xo