Why not make a faux frame for a lightweight piece of art with colorful tape?
DIY Renters Decor Ideas - DIY Bedroom Canopy - Cool DIY Projects for Those Renting Aparments, Condos or Dorm Rooms - Easy Temporary Wall Art, Contact Paper, Washi Tape and Shelves to Make at Home http://diyjoy.com/diy-decor-ideas-for-renters
Cool windows! Tissue paper and electrical tape. - even though this is for a classroom I totally want to do this in my bedroom!
How to hang plates on wall without plate hangers. Great idea...will definitely have to do this. Weird shaped plates don't work with plate hangers.