Cardboard Tube Leaves
Materials: Cardboard tube, paint (yellow, orange, red), paper, paper plate, paintbrush
How to: Squeeze the cardboard tube slightly to create a more ovular leaf shape. Have your child dip the tube in some paint that has been squeezed on the plate and 'stamp' on the paper. If they are interested, you can also help them paint the veins inside the leaf with the paintbrush.
Source: Frugal Family Fun
Updated 10/8/11: I'm linking up to One Artsy Mama!