Fallout 3 is set in post-apocalyptic America after a nuclear war leaves most of the country a radiation filled wasteland. In order to protect the people of America from radiation, the government made bomb shelters. In the year 2277, you (the player) leave the shelter of Vault 101, which is located in our nation's capital, in search of your father, who has apparently run off. If you follow just the main quest of finding your father, the game is relatively short. So my advice to you is to explore as much as you can of the capitol wasteland before finishing the main story line. There are plenty of side quests, interesting locations, and items to keep you busy for weeks. Here are a few things to keep an eye out for on your journey:
1. Unique weapons
There are many different weapon options in the game as well as cool unique weapons that have names. A few of my favorite examples include: A3-21's Plasma Rifle, a minigun named Eugene, a sniper rifle named the Victory Rifle, and the Xuanlong assault rifle.
Throughout the game are Vault-Tec bobbleheads that when found and picked up will permanently improve either one of your S.P.E.C.I.A.L.s or a skill. There are 20 in total, can you find them all?
Good luck finding the alien space ship that crash landed somewhere in the capital wasteland! If you have the add-on Mothership Zeta then finding this ship means you will be abducted. If you don't have the add-on it is still pretty cool and you can get a cool weapon here.
If you like tuning into Galaxy News Radio and listening to Three Dog then you may have heard him mention a place that has green vegetation called Oasis. If you don't mind wandering around some cliffs in order to find the entrance it is a really interesting place to be.
There are a eight characters that, when certain requirements are met, you can get to join you on your quests. They will defend you when you are being attacked and they can carry items for you so that you can travel with more. You can also ask them to wait for you somewhere and they will wait indefinitely until you return for them.
6. Your home
The quest 'The Power of the Atom' will result in one of two possible places you can call home in the game. If you side with the people of Megaton you will get the key to a shack from Sheriff Simms. If you side with Mister Burke you will get a suite in Tenpenny Tower. The choice is yours.
7. Vault experiments
The vaults were supposed to be the only safe place in America after the war, but were they really safe? As it turns out, the vault residents were actually being experimented on by the government. Each vault had a different experiment. By finding clues in each vault in the game you can usually piece together most of what happened there.
8. Roach King
I found this guy randomly while on my way to the Republic of Dave. He sits on a throne and is surrounded by Radroachs. He has a few useful things on him and his throne, including a mininuke.
There are so many really cool, interesting, or just plain random things in this game that you are sure to have a good time playing!