Devour a corpse ( Cannibal perk required): -1 Karma per corpse.
Making a truce between The Family and Arefu.
Siding with the abolitionists during Head of State.
Destroying the Krivbeknih in the Point Lookout add-on: + 500 Karma.
Taking the Escalator to Heaven perk in the Broken Steel add-on: + 2000 Karma (essentially, it resets Karma to the maximum 1000).
Blowing up the Enclave Mobile Command crawler in Who Dares Wins in the Broken Steel add-on +500 Karma.
Activating Project Purity by yourself in the quest Take it Back!: +600 Karma.
Activating the Failsafe in the Tranquility Lane Simulation: +300 Karma.
Disarming the Megaton bomb in The Power of the Atom quest without requesting payment: +200 Karma.
Killing a Very Evil character or creature ( Allistair Tenpenny, Mister Burke, Eulogy Jones, Carolina Red, Ahzrukhal, Jaime Palabras, Jotun, Ymir, Cutter or a cannibal Hunter): +100 Karma.
Saving a wasteland captive without the Reward: +75 Karma.
Giving 25 caps to Mei Wong to buy a gun: +100 Karma.
Performing a good action in a quest: At least +50 Karma (ex: Bring Cherry to Rivet City.).
Giving away purified water, or Aqua Pura with Broken Steel installed, to beggar characters like Carlos outside of Rivet City: +50 Karma per item.
Giving scrap metal to Walter in Megaton's water processing plant for free: +10 Karma per scrap.
Selling fingers taken from the corpses of evil characters (you killed) to Sonora Cruz via the Lawbringer perk: +10 Karma per finger.
Donating caps to a church (In increments of 10, 50, or 100): +1 Karma per cap.
Karma titles above level 20 can only be reached with add-ons. The Karma status is defined by a "Karma title," depending on one's Karma points and level. The Lone Wanderer begins the game with a value of zero, which increases or decreases based on the their actions. Karma levels in Fallout 3 and Fallout: New Vegas