11: As the party approaches, they will hear noises, as though some kind of organ is playing. Upon <s>opening the door</s> entering the room, they will be hit by a blast of steam (3d6 damage. Save for half damage as though a Red Dragon's breath weapon.). Once it has cleared, the party will see strange metal pipes going up to the ceiling, which will open randomly, making the noise they heard on approach.
Back story: Years ago somebody decided to use a Permanency spell combined with Hold Monster on a Fire Elemental and a Water Elemental. They then decided "Well, now that we have these, we might as well do something with them, and devised a steam organ. Said Elementals can be found somewhere below.