The Siren's Deception
Like Benirus' house, this is another quest that can be picked up very early in the game. Talk to almost anyone in Anvil and you'll eventually get a "Gang" topic. It seems that there is a gang of young women who have been seducing and robbing the men of the town. Their latest victim is a fellow named Gogan ("what an idiot," says Wilbur at the Count's Arms), Maelona's husband. You can find both of them wandering around town or in their house near the Count's Arms and either of them can be the quest-giver.
The gang stole a ring from Gogan that was an heirloom from Maelona's family. There's 100 gold in it for you if you can retrieve it. Gogan can also tell you that you're looking for a Nord woman and an Imperial woman. So it's off to the Flowing Bowl in the harbor to find them. The Nord woman is Signy Home-Wrecker and the Imperial woman is Faustina Cartia. They are there anytime that the tavern is open and, regardless of whether you are male or female, one will approach you.
If you are male, Signy will extend an invitation to visit these lonely women in their home at Gweden Farm (kind of southeast of Anvil) with a suggestion of more intimate activities to follow. If you are female, Faustina extends an invitation to join their little operation (remember that Bethesda wanted a "Teen" rating on this). In either event, stop by anytime after 11:00 p.m. to discuss the offer in more detail.
The farmhouse is locked until 11:00, so trying to be early for your appointment won't accomplish much. When the appropriate time arrives, enter and begin the discussion. Depending on whether you're male or female and how you choose to respond, the conversation can proceed in several directions, but it will eventually reach the point where a fight breaks out between you, Signy, Fautina and a previously unknown Khajiit named Tsarinna (what? you thought you might actually get out of this without being a punching bag for someone?).
There are a few things to watch out for once the blades come out. First, that farmhouse is awfully small, making maneuvering difficult and the short ranges might be a problem for spellcasters and archers. Second, if the fight goes on long enough, Gogan and Maelona (in their Anvil City Guard uniforms) will enter the fray, making "friendly fire" a serious issue. Third, you can't preemptively strike because they aren't bad guys until they attack you, so all you can do is wait for them to make the first move.
Once the three are taken care of, Gogan and Maelona give you the 100 gold reward. Search the bodies for goodies, making sure that you get the bedroom key and Faustina's "Witsplitter" dagger (a small Drain Magicka and Intelligence enchantment). The key will not only let you out of the house, but also let you access the basement where you'll find a few more goodies. These include the "Oaken-Hull Family Jewels" from Heinrich Oaken-Hull, Pinarus Inventius' Iron Cuirass and Minotaur horn and Astia Inventius' amulet. The items cannot be returned nor used to further embarass or blackmail their owners (more's the pity). But the whole haul should be worth a few hundred golds and a 1-point Fame boost.