It turns out the achievements in Fallout 3 PC are, in fact, really easy to get--no mods required. As discussed on this week's Bombcast, you can simply drop down the game's developer console, accessed by hitting the tilde (~) key, and punch in the command "addachievement x" where x is a number between 1 and 54, corresponding to the game's 54 achievements. That's including the four added by Operation: Anchorage, which you don't even have to own to get the additional 100 potential points included in that add-on. You can do all this from the game's main menu, without ever starting a new game. That's 1,100 points in about one minute. Scandalous!
I personally verified that this trick does in fact work. 54 times. All in the name of research, you know.
This certainly smacks of last year's achievement frenzy surrounding Avatar: The Last Airbender, which let you rack up the full 1,000 points in about 30 seconds of repetitive action. The key difference here is, Fallout 3 is actually worth your time, notwithstanding the ease of its achievements.
Anyway, this odd turn of events prompted us to seek comment from Bethesda about whether this command was intentionally left in the game or not. VP Pete Hines responded thusly.
There are lots of things you can do using console commands. It's not something we encourage or support.
Doesn't sound like the trick will be removed in subsequent patches, then. So at least for the moment, if you have a yen for achievement points and no shame, it seems Fallout 3 is your game.