Abstract: A fascinating feature of living matter is that mechanical tasks at large length scales are routinely accomplished with exquisite precision by the cooperative action of millions of nanometer-sized molecular motors and fibers. Examples range from cellular motility and division to muscle actuation. From a technological standpoint, it would be highly desirable to spawn materials that could inherit, at least in part, this ability. In this vein, I will describe two biological motor-driven filamentous assemblies that exemplify these remarkable properties and our efforts to both fundamentally understand them and to create new functional materials with them. In first part I will describe the creation of active gels comprised of purified microtubules and motor proteins that consume chemical energy in the form of ATP. Unlike equilibrium polymer gels, these gels are capable of continuous structural remodeling that can drive internal fluid flows and macroscopic motility. In the second part I describe a new experimental platform to measure ATP consumption in swimming sea urchin sperm at the single-cell level. These measurements provide new insight into long-standing questions about mechanical regulation of periodic beating in flagella. Together, these systems highlight the need for new approaches from soft matter physics to understand the unique stress-structure-dynamics relationships intrinsic to motor-driven biological materials.