I like the idea of giving students candy treats with cute notes for test days. This helps give them some energy power to do their test, and helps students with test taking anxiety. The positive notes starts the test day off on a good foot.
rainbow ice cubes - happy hooligans - fun drink for St. Patrick's Day
rainbow water - for St Patricks Day food coloring in ice cubes. Sparkling water for a healthier version of Sprite. another pinner said you could use kool-aid for the ice cube to change the flavor of the water.