BrendaK has great ideas. Why not just ask your granddaughter what she wants to do and show her the steps to do it - just the basics.
My son and daughter learned by watching me sew, then later sitting at my old Featherweight and stitching straight seams to make teddy bear blankets. From there they progressed to middle school/ junior high and learned how to sew fish and pencil pillows. They became hooked.
My daughter is now quilting baby quilts for her best friend. It only takes a couple of minutes to stoke the flame of creativity and look out! You may find yourself the recipient of a quilt from her some day.
Let us know how she does.