We construct a ratchet of the Smoluchowski-Feynman type, consisting of four vanes that are allowed to rotate freely in a vibrofluidized granular gas. The necessary out-of-equilibrium environment is provided by the inelastically colliding grains, and the equally crucial symmetry breaking by applying a soft coating to one side of each vane. The onset of the ratchet effect occurs at a critical shaking strength via a smooth, continuous phase transition. For very strong shaking the vanes interact actively with the gas and a convection roll develops, sustaining the rotation of the vanes. Introduction.-Throughout the ages scientists and laymen alike have tried to find a way to circumvent the second law of thermodynamics and create work out of thermal noise. In 1912, Marian Smoluchowski devised an especially appealing thought experiment [1], which consisted of four vanes and an asymmetrically toothed wheel with a pawl, submerged in a molecular heat bath [ Fig. 1(a)]. At first glance it seems that the wheel can turn in one direction only, in violation of the second law. However, Richard Feynman unambiguously showed that this type of device does not produce work at thermal equilibrium [2]: Since not only the vanes but also the pawl are subject to collisions with the gas molecules, the pawl bounces off the toothed wheel and causes the system to rotate randomly in either direction.In contrast, systems outside of thermal equilibrium are very well capable of creating work (directed motion) out of a noisy environment by means of the ratchet effect [3]. In fact, ratchet type devices have been proposed as the paradigmatic way in which motors operate at Brownian scales [4], and during the last decade scientists have realized (over a limited rotation range) a molecular version of Smoluchowski's device [5]. Here-on a macroscopic level-we construct a fully operational rotational ratchet of the Smoluchowski-Feynman type, capable of any uninterrupted number of revolutions. It consists of four vanes that are allowed to rotate freely in a granular gas. The necessary out-of-equilibrium environment-to bypass the second law of thermodynamics which prohibits the extraction of work from a system at thermal equilibrium-is provided by the granular gas. This is by its very nature out of equilibrium since in order to sustain the gaseous state it requires an external energy input to balance the energy dissipation caused by the inelastically colliding particles. The equally essential second ingredient, the symmetry breaking that must be present in order to rectify the stochastic motion due to the noisy environment, is provided by the fact that the two sides of each vane are coated differently. Although similar devices have been