One of our favorite family activities is visiting local gardens and parks. I often take a sketchbook and pencils with me when we go. After watching me, my children will now often join me with their sketchbooks!
Your local craft store will have inexpensive books and multi packs of pencils. It is a wonderful way to allow children to stop and really look at the details in the world around them. Remember to have them sign and date their work. It is wonderful to watch their skills grow and improve.
I hope that you'll consider blending art and nature with your family.