If you are looking for a toy to spark the imagination, whether for a child or an adult, try Rory's Story Cubes. They are amazing!
http://www.storycubes.com/
We bought some of these for my 4 year old for her birthday. They comprise of 9 dice with different images on each face. Once rolled you have to start by saying 'Once upon a time....' Then you use the images to tell your story.
You can make it as complex of as easy as you want. My youngest daughter likes to choose her images rather than having the randon rolled selection, however the eldest likes to roll them then write the story down. This can be taken as far as you like, you could set a time limit to the story so they have to fill a lenght of time thereby increasing the time they have to spend thinking or make it an association game where they can't actually say the name of the image in the story telling, they have to refer to it in a round about way.
Some of the ideas both of the girls have come up with have stunned me. My favourite so far was told by Rona (the youngest);
'Once upon a time there was an aeroplane and he left a foot print.....' If only she knew!
