A four-year old and a six-year old were able to create these adorable linoleum prints and a tutorial over at The Long Thread will tell you how.
You'll need only a few things really: linoleum, carving tool, paint, etc. Then basically just have your child draw right on the linoleum. You carve out the drawing and then apply the paint.
Such a simple project with such great results! Go get yourself some linoleum for the weekend and head over to The Long Thread for this and many other great tutorials.