Half-Life 2 Garry's mod
Full user review
"Finally, a game in which you do WHATEVER YOU WANT!"
Here is how it works. You choose a level (new levels can be downloaded from websites), or even a stage from HL2, and you are given a gravity gun, and a physics gun. The physics gun let's you easily move, drag, spin, throw, freeze any object. Hold Q to bring up a menu where you click on something, and it appears right in front of you. You can then use tools to rope and weld objects together. You can also make enemies and allies appear. You can do ANYTHING! Here's an example: I make a car appear, I put rocket boosters on it, I make a large pole appear, attatch a rope from the pole to the car, get in the car and use rocket boosters to spin around the pole really fast. lolz