This Old House

 refers to an unmarked and repeatable quest in Fallout 3.

Speak with Winthrop in the Underworld at the Museum of History to unlock the option to bring him up to 5 units of Scrap Metal at once in exchange for Stimpaks or RadAway. This quest is very similar to Walter's Scrap Metal.

This quest can be side-stepped if your Strength, Small Guns, Big Guns or Melee Weapons is high enough to threaten Winthrop into giving you all the Stimpaks, RadAway and Rad-X he has.