Homo Ludens is a book by published in 1938 by Johan Huizinga. It is meant to explain The Play Element of Culture(not just children's play). Homo Ludens is an important part of game studies. As such it is a great place to start out when designing course for children, even very young children. They are immersed in play, and explaining and expanding on something they are genuinely absorbed in daily. As Maria Montessori observed Play is the work of the child.
> the notion of play as a distinct and highly important factor in the world's life and doings...
> even in its simplest forms on the animal level, play is more than a mere physiological phenomenon or a psychological reflex. It goes beyond the confines of purely physical or purely biological activity. It is a significant function—that is to say, there is some sense to it. In play there is something “at play” which transcends the immediate needs of life and imparts meaning to the action. All play means something.