Get it here:www.garrysmod.com
Perhaps the most famous non-game in the canon, Garry's Mod turns Half Life 2 into a building site where ready made objects, vehicles and the laws of physics become your playthings. Create moving cars and working machines or pose Half Life characters like articulated puppets. Play deathmatch games around your creations or take virtual photos of your handiwork. Like a super-sophisticated Meccano set, Garry's Mod gives you a creative sandbox where imagination is the boundary and the rules of play are entirely up to you.
Get it here:www.distractionware.com/blog/?p=759