Perfect for those days when you have 7 minutes left at the end of the period - quick, easy, fun, can be used for all levels, and easy to do in the target language. Would be great with a Smart Board, but will work without one too.
Yes, I made 30 ice cube trays of water colors *stolen from pinterest*. http://littleartsylittlecraftsy.blogspot.com/2012/10/homemade-water-color-paint.html For 30 trays do one color at a time: 1.5 cups baking soda, 3/4 cup vinegar, 1TBL corn syrup, 3/4 cup corn starch. Those are the measurements I used for 30 "cubes" and mix the food coloring with the vinegar 1st for consistent color.