styrofoam covered with fabric wall art. My daughter and I did this for her room. We used cheap painter canvas and scrapbook paper. We sprayed adhesive glue to the canvas and layed the scrapbook paper on top.
Gallery Wall / photo wall - use picture ledges to avoid drilling holes in the wall, easy to move frames around! I REALLY LOVE this idea, especially considering the amount of holes I put in the wall doing our last picture wall.