Tell me a story
    
    generates a children's story. Maybe similar to tracery, but with various configuration options, like a way to choose favorite animals, name the protagonist, choose the location, choose the ending, etc. Use some kind of constraint solver to ensure the preferences are met. Remembers recent configurations and allows making any of them a persistent default for later stories. Optionally uses text-to-speech to read it for you. Remmebers recent plot types and biases towards using new plot types. Maybe word choice and sentence structure could be adapted to grade level. 
    
    It would be nice for it to be illustrated but the asset requirements would be huge, would need to do something similar to scribblenauts probably.
    
    It would be nice to be able to build up to a moral and/or practical lesson.