I couldn't agree more with your post.  Parents and kids seem to be so wrapped up in planned play time that they have forgotten that unstructured play is also a learning experience.

I'm not sure if this fits, but just the other day, I was talking to a friend of mine about a birthday party for his 8 year old daughter.  She wants to go horseback riding or rent some big time activity, neither of which he can afford.  I told him, at my kids birthday parties, we used to do arts and crafts activities.  

In fact, at one such party, we told all the girls to bring a plain white T-shirt, and we supplied the fabric paints and markers.  The girls first planned their designs on paper, then put them on the shirt.  They had so much fun, plus they got to take home a memory of the day.  My daughter was 8 at the time, and now she's 22, but she still has that T-shirt.

BTW, if you're interested, I have a book I'm no longer using entitled, Teachables II, which is subtitled, Homemade Toys that Teach.  It's full of projects using everyday household materials.  I'd love to send it to you.........................:)