Simple 'nuff. We all take turns designing a room, and once the house is finished, we build another.
Creepy stuff galore; the stubler, the better. Floorboards designed to creek? Thats a-okay. Dead bodies? LOLWAT
Bonus points if you give your response to entering the forgeted-up room.
And go.
To be done
Living room
Bathroom
Kitchen
Bedroom A
Bedroom B
Hallway
Attic
Basement
I'll start with the living room.
An old sofa laced with vermin sitting in one corner, a old static-filled TV that erratticly turns itself on-and-off. Floorboards creek. Light fixture flickers with every bulb. Smells like must.
(Pick any room, and GOGOGO)