Murphy's Bombing Run

 refers to an unmarked and repeatable quest in Fallout 3.

Walkthrough
Murphy is a ghoul scientist stationed just inside Northwest Seneca Station who is working on an improved version of the drug jet, known as ultrajet. However, he needs your help with one of the ingredients: Sugar Bombs.

For every box of sugar bombs that you bring him, he offers to pay you 15 caps which can be increased to 30 caps by passing a speech check. You can then purchase 1 ultrajet from him (around 70 caps each) for every 8 boxes of Sugar Bombs you turn in.

Bugs

 * The first time you speak to Murphy, giving him exactly 4 boxes of Sugar Bombs will result in you not getting paid.
 * Fawkes may treat Murphy and his guard as hostile.