2 free printable mandalas on this page (samples from an e-book): http://www.art-is-fun.com/free-mandala-designs-to-print.html (Not suggesting you buy the e-book. Why do that when there are so many fabulous free mandalas? Several saved in albums on the OMazing Kids Facebook page with links to the sources ~ http://www.facebook.com/OMazingKidsYoga)
my uncle used to do the same thing for me. Art With Mr. E: Line Design w/Shading - 4th 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).