I've always enjoyed Origami. The crane with the flapping wings never fails to entertain little ones. I've also memorized flowers, frogs, boxes and others.
I found this site that has free instructions.
http://www.tammyyee.com/origami.html
There are many more, of course, (google 'origami') but this lady also has coloring pages to print and other fun things for kids.
Remember, true Origami starts with a square, and is not cut.
Arts and Craft supply stores have multi-colored packs of Origami paper.
Foil too! *enjoy*
DM