The Sorrowful Suitor

 refers to an unmarked quest in the Fallout 3 add-on Broken Steel.

Walkthrough
In the Presidential metro, right before taking the train to Adams Air Force Base, go up the nearby stairs and you can find a holodisk called sorry, my darling next to a skeleton on a bench. The disk contains the apology of an unnamed woman to her "darling" for not being able to make it to their meeting point in La Maison Beauregard after all he had to go through to get the "special gift" for her.

Arriving at La Maison Beauregard through Georgetown East, you are confronted by a hostile character called Lag-Bolt. Aside from his unique armor and shades, he also carries the key to a suitcase nearby in which you find the "special gift", the all-nighter nightwear.

Reward

 * All-nighter nightwear
 * Lag-Bolt's combat armor
 * Lag-Bolt's shades

Bugs

 * If you listen to the holodisk for the first time (enabling this quest) while in La Maison Beauregard, Lag-Bolt and his suitcase will suddenly appear and, if he sees the player, he will immediately attack.
 * If you have already encountered and killed Lug-nut, Lag-bolt may not appear at La Maison Beauregard, and the quest will not make any sense.
 * To fix this, save before entering La Maison Beauregard, then make sure to go up the pile of rubble, reload if Lag-bolt doesn't appear by this point.