I just remembered that I built a tree house one summer when I was 11. Me and my neighbor had so much fun building that, it was in the forest next to our complex and we used scrap wood and my dad's tools and nails.
Oh boy! I was so excited to see this thread was bumped!! I cannot get over all the WONDERFUL ideas and glad to see others inspired as well! betsy, also, thank you for the wonderful story about the single mom...sometimes I get depressed wishing I could do more for my dd since we are poor but that just proves that what kids remember isn't spending tons of money but simple joys together!