Origami is the art of paper folding, originating from Japan, but now also very popular in the Western world. My favorite origami author is John Montroll, whose books (e.g., Origami for the Enthousiast, Animal Origami for the Enthousiast, Prehistoric Origami) feature very detailed and beautiful models, mostly of animals. At this webpage, a few links, a few photo's, and four simple traditional models where photo's show how to make them.
Photo's show how to fold some easy and well known traditional paper folding models.
Excuses for the poor quality of these pictures. More pictures can be found at the links given above.