Fallout 3 random encounters

Throughout the world of Fallout 3, you can encounter random events in the Wastelands. There are certain places where random encounters can happen, but once "activated", a random encounter in a particular area won't change.

You can save outside the spawning area and keep reloading if you don't get the encounter you want.

Random Encounter Locations
These are the known locations so far:

Types of Random Encounters
=Wastelanders, Scavengers, Slavers, Beggars, and Uncle Leo=
 * A Giant Radscorpion fighting a Giant Ant
 * A Wasteland Doctor.
 * A Wasteland Junkie.
 * A Scavenger with one or more of the following pets: a Brahmin, Dog or trained Yao Guai. He'll offer you a Nuka-Cola Quantum.  You can barter with him into reducing the price.
 * Two Wasteland Settlers and two Escaped Slaves fighting over a refrigerator of 10 Purified Water.
 * Two Wastelanders pondering an Enclave Eyebot that hovers around them consistently (as opposed to a long patrol like most).
 * Three Hunters.
 * A lone Hunter selling meat.
 * A Wasteland Merchant. After having a talk with him about the Great One, he'll collapse and die.  You'll find a Wasteland Merchant Note on his body about him going to Oasis the next day.
 * Uncle Leo, a friendly Super Mutant. If you tell him you're going to rob him, he'll give you a Dirty Pre-War Businesswear as a present. If you attack him he'll run away instead of fighting.
 * A Scavenger with his malfunctioned Mister Handy. If you repair it, the Scavenger will give you two Energy Cells.
 * Ghoul Wastelanders around a burning barrel.
 * Three Slavers with three Slaves.
 * A man named Ben Canning. He asks for purified water.
 * A Wastelander killing and looting a molerat (only after completing the Wasteland Survival Guide quest). He has different dialogue options, depending on whether or not the player completed all bonus objectives given by  Moira. If the player says he has helped with the book, a congratulatory or a mocking response is received. If the player says he has never heard of the guide, the Wastelander will provide him with a copy of the book.
 * Two Hunters attacking a Giant Worker Ant.
 * Three Hunters attacking a Vicious Dog.
 * A Deathclaw and a dead Wastelander. You can find Deathclaw Gauntlet schematics for the Deathclaw Gauntlet on the dead Wastelander.  (It is possible to save him; dialog will get you the schematics and a location marked on your map where he was attempting to go.)
 * Two to Three Wastelanders fighting a Deathclaw. (Note that the Wastlanders DO NOT have the schematics for a Deathclaw Gauntlet.)
 * Mel, a modern Highwayman who will demand caps and items from you. You can either utilize speech options, or kill him.
 * Laszlo Radford (He's hostile and will open fire on you with his Railway Rifle).
 * Sam Warrick shooting at a Wastelander (if he kills the Wastelander, he'll turn on you).
 * Five Raiders, four beating the fifth one from all sides, in turns. It seems to be an initiation.
 * Three Raiders and a Wastelander with a time-bomb on him. You can disarm the time-bomb if you have a high enough explosives skill.
 * Three Wastelanders with info about Oasis. If you ask them about it they'll turn hostile.
 * A Scavenger and his dog or Yao Guai fighting a Protectron, Robobrain or Super Mutant. If you go near the Protectron/Robobrain/Super Mutant after you kill it and the Scavenger is still alive, he'll attack you.  Oddly enough, if you kill him, it results in negative karma.
 * Mole Rats attacking a Wastelander (if you save her she'll give you a small amount of caps).
 * Radscorpions attacking a Wastelander.
 * Two Wastelanders fighting a Giant Radscorpion over a fridge of 8 purified water.
 * Vicious Dogs attacking a Raider, Wastelander, or Slaver.
 * One or two Hunters fighting a Yao Guai.
 * 3 Hunters attacking a Giant Soldier Ant.
 * A Deathclaw surrounded by the bodies of various robots, wasteland creatures, raiders, slavers and wastelanders.
 * Three Wastelanders fighting with a Deathclaw. If you save them they'll give you the location of Rock Creek Caverns.
 * Two Slavers who will shoot you if you fail the speech challenge.
 * A Vicious Dog, two dead Vicious Dogs, and a dead Wastelander.
 * Two or three Ghoul Wastelanders in a stand-off with two or three Wastelanders or Slaves over a fridge full of purified water. You will get half of the water for helping one side to kill the other.  If you arrive after one side has already been killed (usually the non-ghouls), you can also attempt a Speech check to take half of the water.
 * Wastelander's body has John's Key and a Wastelander Note which starts you on the John's Treasure Box unmarked quest.
 * A few Escaped Slaves who have a few dialogue options if you talk with them: if you know where the Temple of the Union is, you can give them the correct directions for some positive Karma, or lie to them for negative Karma, or just say goodbye.
 * Three Hunters chasing and attacking a Wastelander. Killing the hunters results in positive Karma, and they carry strange meat, indicating they are roaming cannibals
 * A giant Radscorpion fighting 3 Giant Worker Ants

=Karma Related=
 * A Talon Company ambush if you have a Karma rating of Good.
 * A Regulator ambush if you have a Karma rating of Evil.
 * A Hitman ambush if you have a Karma rating of Neutral.

=Helpful=
 * A UFO exploding overhead, dropping Firelance and spilling exactly 24 Alien Power Cells all over the area. It helps to have Dogmeat search for the remaining ammo if you can't find it.  Also, if you get this encounter to spawn near a building like the Super-Duper Mart, it's possible the ammo or the gun will clip through the building.  The only way to get the ammo is to have Dogmeat search for the ammo or gun, then when he is running up against the structure you can push him through it.
 * If you have not recruited Dogmeat, it is possible he will appear during random encounters to come to your aid.
 * You'll receive a Chinese Radio Beacon over your Pip-Boy. You'll find a Dead Chinese Commando at the spawning point.
 * Two Frag Mines and two Wastelanders, one of whom attempts to disarm them (unsuccessfully).
 * Four Frag Mines scattered with no one around.
 * A dead scavenger with random items.

=Brotherhood Outcasts=
 * Two Brotherhood Outcasts and a Protectron.
 * Three Brotherhood Outcasts, two with Laser Rifles and one with a Gatling Laser
 * A small squad of Brotherhood Outcasts being chased by two Deathclaws.
 * One Brotherhood Outcast Robobrain
 * Two Brotherhood Outcasts with a Robobrain.
 * Two Brotherhood Outcasts armed with a Laser Rifle and Missile Launcher fighting two Yao Guai.
 * Three Brotherhood Outcasts armed with power fists.

=Other=
 * Three Megaton refugees who attack you with knives (available if Megaton is destroyed)
 * A Vertibird getting hit by a missile and crashing near you.
 * A random number (up to four) of Mad Brahmin.
 * One or more (up to four) Giant Ants fighting a Giant Radscorpion.
 * One to four Giant Ants around a toxic barrel with one being bigger than the others.
 * Dead Vault 101 dwellers and a giant Radscorpion (If you drove the Vault 101 dwellers out of the Vault).
 * Amata being questioned by two hostile Enclave soldiers and a non hostile Enclave officer; if you talk to her, move too close to the soldiers, let the soldiers finish talking to her, or attack the soldiers, Amata will be killed (you can save her for no reward or dialog options, she will only say this is all your fault even if you convinced her that her father destroyed the Vault).
 * Susie Mack, if you made Amata the Overseer of Vault 101 during Trouble on the Homefront. She will tell you that the Vault is doing fine and give you purified water.
 * Two Protectrons dueling.
 * If you capture a large amount of slaves, you may randomly be attacked by a group of four slavers seeking to eliminate you as competition because you have made them look bad.