Hollowed-Out Rock (Fallout 3)

The  is a secret stash where you can obtain a Sniper Rifle and other various items that might be useful early in the game.

Location
The location is around the back of Megaton. Usually you will be attacked by three Mole Rats very close to the end.

Loot

 * Sniper Rifle and ammunition
 * Stealth Boy
 * 5 Stimpacks
 * A note, As Requested

Trivia
This is a clear easter egg relating to Morrowind, as in a "Hollow Treestump" behind Thirsk, there is a "Blood-Stained Note" with the message:

YouTube Videos
Location of the Hollowed-Out Rock's hidden loot 9Zdig-cAhXE