Garry's Mod for Half-Life 2 lets you take complete advantage of the physics system by giving you tools to sculpt the world objects as you see fit. Put characters in awkward poses, create your own wheeled vehicles, or even attach objects to flying scanners.

GMod is a Sandbox Modification. Using GMod you can pose ragdolls. This means can position people from HL2 and change their faces. A big comic book creating community has popped up around this feature. Using GMod you can build. Take props from HL2 and weld them together to make walls. Axis a wheel to it to create a working car. Rope some cans to the back. A big contraption creating community has popped up around GMod - creating such things as Rube Goldberg devices, catapults, cannons, bridges etc.. Using GMod you can make your own weapons. That's right, make your own weapons. Using Lua you can create a custom weapon to do just about anything. If you're new you can change simple things like rate of fire, models, sounds. If you're awesome the world is your oyster, mass changing guns, melon cannons, jetpacks. GMod gives you the freedom to do any of these things in single player or online with your friends.