I loved doing this in art class. Art With Mr. E: Line Design w/Shading - Grade Very cool, fun art shading project from Art With Mr. E. he's an elementary art specialist. Try this with your kids (but I think grown ups would enjoy this too).
Hope Studios: Tutorial Tuesday - Button Bracelets Buttons in various sizes (test to be sure your cord will fit into the holes) Round leather or coated cotton cord mm in diameter) Instructions: Arrange your buttons ahead of time to lay out your pattern
Hand painted tree rings - would recommend putting all tree rings on a board (which could be painted a coordinating color to add pop to the art piece. Really neat idea for after school kids. Might just do 9 rings in a square frame!
My son has a fascination with the moon so this would be perfect picture this. a bedroom wall, painted in blue-black chalkboard paint, chalk drawing of the moon, and finished with a curtain of white holiday string lights.