Bendebec, here you go:
Unlocking the overground Vault 87 location on your Pipboy.
(bring lots of Radaway)
The location will be on your Pipboy when you pick the Explorer perk. You should to approach from the high ridge and keep running past the doorway (it's locked) and pause every second to drink Radaway as your rads will be flying up at an insane rate.
Murderous Gnome in the Presidential Metro:
This is at the very end of the rail tunnels, past the door where you meet the computer. (Broken Steel DLC only)
The physics trap in the shop in Jury Street:
Again, find Jury Street Metro with the explorer perk, it is a little West of Megaton. The shop is opposite the diner.
Sniper Rifle in a rock behind Megaton:
Follow the outer wall around, kill the molerats and look for a rock surrounded by tree stumps, very near the wall. You can open it.
Launching nukes from Fort Constantine:
You can only do this if you have the keys from the 'You Gotta Shoot em in the Head quest'. There's a terminal in the underground area that launches the nukes.
Madame Jealle's Reading Room for the Discreet Gentleman in L'Enfant PLaza:
It's on the main street in behind a building in an alleyway
Lucky Shades:
On a manikin in Lucky's Grocer (a little down the hill from Tenpenny Tower and the metro tunnels). These are well worth finding as they give you an extra point of luck!
Grey Bandana from Raider in Jury St metro