Fallout 3

Game Cheats:
Brahmin Tipping
If you come upon a wild Brahmin anywhere in the wasteland (not a pack Brahmin) crouch and hit the interact button to tip the Brahmin.

Alien and Alien blaster
From the Minefield head north. Keep going and you'll eventually pick up a radio signal from alien space craft. When you find it there will be a space craft and special gun with limited ammo somewhere in the area.
Easy experience points
When creating a character, tag the Speech skill. After exiting Vault 101 and reaching level 2, put all your skill points in Speech. This will allow you to easily exploit the glitch. Go to BigTown, located just east of Arefu. You may need to go to Megaton and speak to Lucy West to obtain the Arefu marker if it is your first run through. Talk to everyone in BigTown, leaving Pappy for last. He has a "Speech" option that remains for the duration of the game. Every success you get using the "Speech" option will net you 6 experience points. Multiple successes will stack, leading to larger point gains. There is no need to wait for fear of losing experience points. Just continue to use the "Speech" option until you level. You must stop talking to him to distribute points. Save the game after leveling up each time, as the game has a tendency to glitch which cause the loss of all your progress.

Have Fawkes and Star Paladin Cross as your followers at the same time
Play until to the point where you meet Fawkes. After he is freed and gives you the G.E.C.K, leave and do the Raven Rock quest. When you see Fawkes outside, tell him to be your follower then proceed to the Citadel and talk to Star Paladin Cross. When she says "I have something to ask you", respond with the second answer. She will say you have a wry wit like your father and ask to join you. Say that you would be honored and she will automatically join you. You now have both Fawkes and Star Paladin Cross as your followers.

Wear up to four head gear items at once
When you acquire the Chinese Stealth Armor, equip it then select up to four hats (for example, Eulogy's Hat, Winterized Power Helmet, Shady Hat, and Ledoux's Hockey Mask). When you have the desired hats you can equip any armor desired. Do not unequip the hats or you will have to do the stealth armor trick again.

Bobblehead locations
Collect the following hidden bobbleheads to gain +10 to a skill or +1 to a stat.

Stats
Strength: Megaton, in Sherriff Lucas Simm's house.
Perception: Republic Of Dave, on a bookshelf on the right in the Museum of Dave.
Endurance: Deathclaw Sanctuary, at the entrance on a table next to a rotting Brahmin corpse.
Charisma: Vault 108, in the Cloning Lab.
Intelligence: Rivet City, on Dr. Li's table in the Science Lab.
Agility: Greener Pastures Disposal, in the small office covered in radiation.
Luck: Arlington Cemetery North, in the basement on a shelf directly below the stairs inside the house to the north.

Skills
Barter: Evergreen Mills, in back of the Market Bazaar on a shelf in the upper-right side behind the Raider Trader that does not attack.
Big Guns: Fort Constantine, in the basement of the CO Quarters inside a safe in the wall.
Energy Weapons: Ravenhold
Explosives: WKML Broadcast Station, turn on your local map. Go through the doorway to the sealed cistern and find it.
Lockpick: Bethesda Ruins, in Bethesda Offices East on the top floor near the door to the bridge.
Medicine: Vault 101, on your dad's desk when leaving.
Melee Weapons: Dunwich Building, just before you leave the Virulent Underchambers, on the floor next to the door.
Repair: Aerefu, in Evan King's house.
Science: Vault 106, on a table in middle of the living quarters second level main room.
Small Guns: National Guard Depot, go through the training room and offices to exit from a door to the main room. Use the power switch on the wall to your left and enter the Armory door, then search the shelves.
Sneak: Yao Guai Tunnels, on top of a metal box in the Den, on the right of the map near some water.
Speech: Paradise Falls, on a table inside Euology's pad (Slave Master's house).
Unarmed: Rockopolis, go directly west from Casey Smith's garage. Look for tattered banners that are strung up. Use your local map to find it.
V.A.T.S. Spotting
If you?re heading into seemingly-hostile territory or simply want to survey the area around you for enemies you might not yet see, try hitting the VATS button over and over again as you make your character turn around, searching all angles. Doing so will alert you to any enemies you may not yet see by zooming in on them in VATS mode. You?ll realistically be unable to do damage to your foes from such a distance, but it?s a good way to spot foes before they spot you so you know what you?re getting yourself into before the crap hits the fan.

Achievements:
Complete the following tasks to unlock PlayStation3 trophy rewards.
whitetop
Vault 101 Citizenship Award (Bronze): Got the Pip-Boy 3000.
The G.O.A.T. Whisperer (Bronze): Took the G.O.A.T.
Escape! (Bronze): Completed "Escape!".
Following in His Footsteps (Bronze): Completed "Following in His Footsteps".
Galaxy News Radio (Bronze): Completed "Galaxy News Radio".
Scientific Pursuits (Bronze): Completed "Scientific Pursuits".
Tranquility Lane (Bronze): Completed "Tranquility Lane".
The Waters of Life (Bronze): Completed "The Waters of Life".
Picking up the Trail (Bronze): Completed "Picking up the Trail".
Rescue from Paradise (Bronze): Completed "Rescue from Paradise".
Finding the Garden of Eden (Bronze): Completed "Finding the Garden of Eden".
The American Dream (Bronze): Completed "The American Dream".
Big Trouble in Big Town (Bronze): Completed "Big Trouble to Big Town".
The Superhuman Gambit (Bronze): Completed "The Superhuman Gambit.
The Wasteland Survival Guide (Bronze): Completed "The Wasteland Survival Guide".
Those! (Bronze): Completed "Those!".
The Nuka-Cola Challenge (Bronze): Completed "The Nuka-Cola Challenge".
Head of State (Bronze): Completed "Head of State".
The Replicated Man (Bronze): Completed "The Replicated Man".
Blood Ties (Bronze): Completed "Blood Ties".
Oasis (Bronze): Completed "Oasis".
The Power of the Atom (Bronze): Completed "The Power of the Atom".
Tenpenny Tower (Bronze): Completed "Tenpenny Tower".
Strictly Business (Bronze): Completed "Strictly Business".
You Gotta Shoot 'Em in the Head (Bronze): Completed "You Gotta Shoot 'Em in the Head".
Stealing Independence (Bronze): Completed "Stealing Independence".
Trouble on the Homefront (Bronze): Completed "Trouble on the Homefront".
Agatha's Song (Bronze): Completed "Agatha's Song".
Reilly's Rangers (Bronze): Completed "Reilly's Rangers".
Reaver (Bronze): Reached Level 8 with Bad Karma.
Mercenary (Bronze): Reached Level 8 with Neutral Karma.
Protector (Bronze): Reached Level 8 with Good Karma.
Harbinger of War (Bronze): Reached Level 14 with Bad Karma.
Pinnacle of Survival (Bronze): Reached Level 14 with Neutral Karma.
Ambassador of Peace (Bronze): Reached Level 14 with Good Karma.
Doesn't Play Well with Others (Bronze): Killed 300 people.
Slayer of Beasts (Bronze): Killed 300 creatures.
Psychotic Prankster (Bronze): Placed a grenade or mine while pickpocketing.
Take it Back! (Silver): Completed "Take it Back!".
Scourge of Humanity (Silver): Reached Level 20 with Bad Karma.
Paradigm of Humanity (Silver): Reached Level 20 with Neutral Karma.
Last, Best Hope of Humanity (Silver): Reached Level 20 with Good Karma.
Weaponsmith (Silver): Made one of every custom weapon.
Silver-Tongued Devil (Silver): Won 50 Speech Challenges.
Data Miner (Silver): Hacked 50 terminals.
Keys are for Cowards (Silver): Picked 50 locks.
One-Man Scouting Party (Silver): Discovered 100 locations.
Yes, I Play with Dolls (Silver): Collected 10 Vault-Tec Bobbleheads.
The Bigger They Are… (Gold): Kill all the Super Mutant Behemoths.
Vault-Tec C.E.O. (Gold): Collected 20 Vault-Tec Bobbleheads.
Platinum Trophy (Platinum): Collect all other 50 Trophies for this Trophy
Trophies Mothership Zeta:
Unlockable How to Unlock
Alien Archivist (Silver) Collected all Alien Captive Recordings
Among the Stars (Silver) Completed 'Among the Stars'
Not of This World (Silver) Completed 'Not of This World'
This Galaxy Ain't Big Enough... (Gold) Completed 'This Galaxy Ain't Big Enough...'
Trophies Point Lookout:
Unlockable How to Unlock
A Meeting of the Minds (Gold) Completed 'A Meeting of the Minds'
Bog Walker (Silver) Discovered all Locations within Point Lookout
The Local Flavor (Silver) Completed 'The Local Flavor'
Walking With Spirits (Silver) Completed 'Walking With Spirits'
Online Trophies:
Unlockable How to Unlock
Agatha's Song (Bronze) Completed "Agatha's Song"
Ambassador of Peace (Bronze) Reached Level 14 with Good Karma
Big Trouble in Big Town (Bronze) Completed "Big Trouble in Big Town"
Blood Ties (Bronze) Completed "Blood Ties"
Data Miner (Bronze) Hacked 50 terminals
Doesn't Play Well with Others (Bronze) Killed 300 people
Escape! (Bronze) Completed "Escape!"
Finding the Garden of Eden (Bronze) Completed "Finding the Garden of Eden"
Galaxy News Radio (Bronze) Completed "Galaxy News Radio"
Harbinger of War (Bronze) Completed "Following in His Footsteps"
Head of State (Bronze) Completed "Head of State"
Keys are for Cowards (Bronze) Picked 50 locks
Last, Best Hope of Humanity (Bronze) Reached Level 20 with Good Karma
Mercenary (Bronze) Reached Level 8 with Neutral Karma
Oasis (Bronze) Completed "Oasis"