The laws of equilibrium statistical mechanics impose severe constraints on the properties of conventional materials assembled from inanimate building blocks. Consequently, such materials cannot exhibit spontaneous motion or perform macroscopic work; i.e., a fluid in a beaker remains quiescent unless driven by external forces. Inspired by biological phenomena such Drosophila cytoplasmic streaming, our goal is to develop a new category of soft active materials assembled from animate, energy-consuming building blocks. Released from the constraints of the equilibrium, such internally driven materials are able to change-shape, crawl, flow, swim, and exert forces on their boundaries to produce macroscopic work. Active liquid crystals can serve as a platform for developing novel material applications, testing fundamental theoretical models of far-from-equilibrium active matter and potentially even shedding light on self-organization of living cells.