Fallout 3 is a post-apocalyptic role-playing game from the creators of the Elder Scrolls series, Bethesda Softworks. The game is set 200 years after a nuclear war almost completely annihilated the entire human race, if not for the Vaults which are underground bomb shelters set up by the government. You play as the 'Lone Wanderer', a young adult who lived in Vault 101 his/her entire life and escaped into the decimated ruins of Washington DC.
The main goal you are given at the start of the game is to find you father who apparently escaped the Vault just before you did. You can follow this goal if you want but the main focus of the game is the seemingly limitless opportunities and exploration and can have in the game world, which may seem a bit strange at first since this is a barren wasteland. There's over fifty hours of enjoyment to be had by just exploring the world and completing quests so this is a large game, definitely one if you want a game to invest a lot of time in.
Fallout 3 looks like a real-time first person shooter at first but elements of a turn-based system are pushed in through a mechanic called VATS, a targeting system where you can aim at a particular part of the enemy's body and let numbers decide the outcome of battle. The main idea of this is to give battles a more cinematic appearance to it. A problem with this is that it oversimplifies combat altogether by being able to just run up to enemies and blowing their heads off at short range.
Fallout 3 is a great, immersive game which, despite the obvious glitches and bugs, provides the player with hours and hours of entertainment and enjoyment.