The Dark Brotherhood Forever

This is a repeating loop of quests that can be completed multiple times, after all previous Dark Brotherhood quests have been completed.

Speak to the Night Mother
Night Mother in her sarcophagus is located in the upper level of the Dawnstar Sanctuary, actually quite close to the main exit. She will inform you that a randomly chosen stock NPC has performed the Black Sacrament, and that you must go and speak with them.

Speak with the contact
Follow the Night Mother's instructions to find the contact. He/she will inform you of who they want killed and pay a levelled amount of for your service.

Kill the target
There are many possible stock NPC targets you can have, spread across all of Skyrim. The locations are:
 * Dawnstar – Nervous Patron
 * Dragon Bridge – Corrupt Agent
 * Falkreath – Seasoned Hunter
 * Ivarstead – Beautifull barbarian
 * Katla's Farm – Big Labourer
 * Kynesgrove – Itinerant Lumberjack
 * Markarth – Scheming Servant
 * Riften – Wary Outlaw or Poor Fishwife
 * Rorikstead – Unemployed Labourer
 * Solitude – Dishonoured Guard or Travelling Dignitary
 * Whiterun – Blasphemous Priest or Visiting Noble
 * Windhelm – Desperate Gambler or Coldhearted Gravedigger
 * Winterhold – Reckless Mage

After you have killed the target, the quest will be complete, but a new quest of the same name will then be given to you, instructing you to once again speak to the Night Mother and receive another contract. This can be done as many times as you want and is a moderate source of income.

Ewige Treue der Dunklen Bruderschaft