I love this idea! I used to pain acorns and pine cones all the time when I was a little kid. Then my friend and I would play with them on the sidewalk (very active imaginations, needless to say!).

Thought you might also like this site- www.uncleenvelope.com. Families can sign up for UncleEnvelopes crafts and he will send one paper craft a month. All the art projects are really cool and they come with a story about UncleEnvelopes most recent adventure.
There are also some print and color sheets for rainy days!

Hope to see you there and keep up the awesome suggestions!