If you have older kids this is a good project to talk about positive and negative space and if you have younger kids it combines a whole lot of awesome things- sticky tape, messy paint, and (kinda) taking apart already done work!
-painter's tape or masking tape
Have the kids lay out a design in tape on their piece of paper. It can be anything, even words. After they've taped up the page, paint over the tape. When the paint is completely dry, carefully peel the tape off the paper (it's easier to peel off of construction paper than computer paper) and check out the newly revealed picture!
Miss Lucy's Examples: