Now that you mention Feynman I recollect that I actually used one of the games/stories from Feynmans autobiography for my children: A story of some very small dwarfs that wandered thru a strange land of regular red and blue trees: Ants on a carpet. It was very interesting for my second son who has a very high interest in plants and animals and who after I told the story took his pocket microscope http://www.amazon.de/gp/product/B000OZXY22/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1 and looked at the capet and said: 'it looks like grass'.