Tissue paper cut-outs on canvas. Spray with water until the colors begin to bleed. Allow to dry completely, tip canvas and tissue should fall off. If it doesn't, allow to dry more. Coat with a clear coat preserver. (Some tissue is color-fast and won't bleed; test first.)
Easy Seasons Tree Painting idea
How to Make a Melted Crayon Wall
15 Ideas to Make String Arts
DIY String Heart | Materials Needed: piece of wood, string, box of nails, spray paint to paint the wood, white paper to draw the heart on
How to make Push Pin Art from The Jones Way blog... could be used with studs or rivets as well... love it!