Action modular origami combines modular and action origami (folding paper). Modular origami involves joining several identically-folded units, without cutting or gluing, into a structure such as a polyhedron. It is well-suited for learning mathematics and the assembly is a kind of puzzle. An appealing type of origami is action origami which moves, spins or changes shape. I discuss the art, craft, engineering and mathematics of action modular origami.