Garry’s Mod is a sandbox mod for the Source Engine. Unlike normal games there aren't any predefined aims or goals. Players are given tools and are left to entertain themselves. The player is in a world where objects can be created and destroyed on demand. Where people can be created and destroyed with the click of a mouse. A world made for him. A world he made.
Fun game, I was laughing out loud the whole time when I first tried it!
Some great amount of thought has gone into making this game as silly as it could possibly be. =)
That said, this game could use some better way of manipulating objects, some kind of standard axis tool rather than using the Physics Gun for everything.
Still, I never thought I could have so much fun in a Source game/mod.