The Houses of Silence is another side-trek from Dungeon Magazine #156, which takes players to a kind of minotaur graveyard far to the west of the Seven-Pillared Hall.
The impetus to come here arrives from another resident of the Seven-Pillared Hall. Terlen Darkseeker is an explorer who does work as a guide for travellers, operating out of the Seven-Pillared Hall. Recently during his travels he stumbled across the Houses of Silence, where he activated a lingering curse intended (in a rather vague way) to dissuade graverobbers.
Now when he delves too deep into the Labyrinth the curse transfigures him into a violent, uncontrollable werewolf. Terlen doesn't remember these transformations and no-one who's witnessed one has survived to tell the tale. The quest starts when PCs engage Terlen as a guide, fall victim to his lycanthropic attack, and then presumably subdue him until he changes back into a human and learns of his affliction.
Terlen's condition has a charming resonance with the idea of the Underdark as the human subconscious; when he "delves too deep" he loses his ability to reason and becomes a creature of pure instinct. There's not really a lot of chance to play that up but it's still a nice touch.
In any case, players who attempt to help Terlen out will be directed to the Houses of Silence.
Much like the other side treks, the Houses of Silence break the pattern of doors-and-runners that Thunderspire has so comfortably settled into. It relies on an extended (and very dramatic) trap to engage player interest. The main chamber is divided into three forks; the left and the right forks end at single minotaur statues, while the main passage terminates at two minotaur statues holding a gong.
When players approach the gong, or when either of the side-corridor minotaurs make "eye contact" with a PC, the trap springs. Starting from the single statues, oil filled cressets on the walls burst into flame, blasting everyone nearby and engulfing the corridor in an ongoing inferno. On subsequent rounds, the flames progress up the corridor, driving players towards the room with the gong, where the next threat waits - a pair of flame-resistant hellhounds and a wraith that can walk through walls. All three take advantage of being able to enter terrain the PCs can't to deliver vicious attacks with only minor fear of retaliation.
Given the history of the place, the wraith is, presumably, a minotaur wraith, which sadly is not illustrated with the awesome piece of artwork that that concept brings to mind.
It's also worth noting briefly that both the original Thunderspire writers and Greg Bilsland on the side treks have managed to keep their devils and demons straight, which is noteworthy mostly because I always forget and use them interchangeably. Devils hail from the Nine Hells and are associated with gods such as Asmodeus (and indeed, two appear in the Horned Hold). Demons come from the Abyss and pay homage to masters such as Baphomet - and, as expected, both here and in the Well of Demons we'll find only demons, not devils. I've never really grokked the arbitrary distinction but it's nice to see that they're at least keeping their story straight.
My guys didn't get to run the Houses of Silence, so I don't know how it works in practice; it seems like it could either be dramatic and exciting, or misfire and end up with players either locked out of the encounter by a wall of fire or frustrated by the cheap tactics of the hounds and the wraith.