GMod, also known as Garry's Mod, is a "sandbox" mod for the first-person shooter computer game Half-Life 2. It allows the player to manipulate objects, often with interesting results thanks to the game's Havok physics engine. This includes any object that has physical properties, ranging from cinder blocks and seagulls to decrepit automobiles and washing machines and much more. The construction of complex machines within the game could be said to be a contemporary spin on the Rube Goldberg machine principle.
