Decimeter-scale robots can use a wide range of techniques to maneuver in challenging environments in spite of lacking the actuated degrees of freedom typically seen in larger robots. Agile maneuver for these small robots greatly benefits from a high power-to-weight ratio and mechanical design which can exploit environment interactions, in addition to explicit control strategies. We have found that many aspects of agile behavior can arise from intrinsic mechanics, which is particularly useful for under-actuated systems. For these systems, appendages such as claws and tails greatly improve maneuverability. In addition, cooperative behavior can be used to increase degrees-of-freedom and agility. The smart composite microstructures (SCM) folding fabrication process, which combines distinct layers for structure and joints, has led to high power-to-weight and robust millirobots. In the future, folding fabrication could be incorporated in robot systems to enable in-situ customization or repair.