Reasoning on the properties of computer systems can often be reduced to deciding the winner of a game played on a finite graph. In this paper, we introduce GAVS, an open-source tool for the visualization of some of the most fundamental games on finite graphs used in theoretical computer science, including, e.g., reachability games and parity games. The main purpose of GAVS is educational, a fact which is emphasized by the graphical editor for both defining game graphs and also visualizing the computation of the winning sets. Nevertheless, the underlying solvers are implemented with scalability in mind using symbolic techniques where applicable.