House for sale

Have someone pretend to be a house salesman who's showing some people around a house. On the outside everything will seem normal but as they walk into the house everything goes mad.

You could just have something completely strange in the first room and let that be that, like it looks like a brothel once you open the door. Or at the start of the tour there's a porn magazine or something small like that on a table, and the salesman says something like "Sorry about that, the owners haven't really had a chance to clean everything, hope you don't mind." And as you go through the house there's something strange going on in each room. 

You could have a half pipe in the bathroom, a fake toilet with someone on it beside the fridge in the kitchen, a group of lads doing drugs in one room, all the furniture stuck on the roof in another room, a weapons lab in another, a klan meeting in another, and some prostitutes in another. Generally just a whole load of completely mad stuff that you wouldn't expect to happen when looking at a house. And just see how long the viewers will put up with it.