Garry's Mod

Rating: 10/10

Many people don't know of this game, but they really should. Garry's Mod is a full-on sandbox game where you can literally do whatever you want. Running on the Source Engine, the same engine that powers Half-Life 2 and Counter Strike, it allows you to do pretty much anything you can think of. You can enjoy over thousands of addons such as maps, weapons, NPC's, and playermodels on Singleplayer, or you can host your friends in a private server. You can also play with your friends on Multiplayer, with a huge amount of game modes such as Prop Hunt, where you can either hide as a normal prop placed on the map, or hunt down all the props as the hunters. You can play Deathrun, where you have to make it through nearly-impossible obstacle courses in order to win. You can also play TTT where you play as a terrorist trying to hunt down the traitors in your group. There are many other gamemodes like Murder, or Jailbreak that are very popular. While all this is great, there are a few downsides. For example, many addons require the support of other Valve games such as Counter Strike or Portal for textures and models. But you can download these legally and for free on various websites. While I have done a good job explaining GMod to you, you can never really understand it until you are actually playing it, which is why it only costs $10. So go, stop reading this, download Steam and buy it, right now.

Steam: http://store.steampowered.com/

Garry's Mod: http://store.steampowered.com/app/4000/

Posing NPC's and camera shots in Sandbox

Sandbox in Gmod

Jailbreak in Gmod

Deathrun in GMod

Prop Hunt in GMod

TTT in GMod

Murder in GMod