Age Level: Any
Supplies: Cardboard headed for recycling, tissue paper (used is fine), paint brushes (1 inch is great), watered down glue, Mod Podge or any other kind of decopage medium.
Full instructions here.
P.S. I found the unique shaped cardboard pieces cut and ready to go outside the sculpture studio at my University, they looked like shields so we decided to put initials on them.