50 Things to Do in the Capital Wasteland

Crispy Gamer has put together a pretty good list of fifty things you may or may not have realized you can do while wandering through the Capital Wasteland in Fallout 3.
Nuke it from orbit: Megaton isn't the only town players can reduce to a smoking crater. Follow the Broken Steel quest line and eventually find yourself at a panel that controls a satellite missile system with targeting data for Rivet City, Project Purity, Megaton and the Citadel. We won't tell you what happens when you flip the switch. Just don't forget to get out of Dodge when you opt to destroy the Adams Air Force Base Platform. That's where you're standing.
Where: Mobile Base Crawler (Broken Steel).

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Hack the right way: There's a right way and a wrong way to hack in Fallout 3. The wrong way is to make blind stabs at a password, then try to reason your next best guess from the number of letters you got right. The right way is to first narrow your options. Move the cursor through the garbled text looking for open parentheses, brackets and carats. If there's a matching closer to the right of them, you can highlight the whole area and select to remove one of the dummy passwords or reset your number of guesses.
Where: All over the Wasteland.

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Study up on H.P. Lovecraft: The vile influence of C'thulu and his minions reaches even into the Wasteland. In the Dunwich Building you'll find a series of recordings that form a breadcrumb trail down to the basement, where an unholy (and irradiated) Obelisk waits. The story seems to stall there, but hidden in Point Lookout is another part of the puzzle. There you can find the profane book "The Krivbeknih"; instead of destroying it, return it to its rightful place at the Dunwich Obelisk, and despair.
Where: Dunwich Bulding.