I watched this movie a very long time ago on TV but here is what I remember:
People move into a very strange old house.
A little girl knows something about it (or is one of the first to find a strange room through a key she found or maybe a dollhouse?).
There is some backstory to the house where the owner built a room to appear as if it's upside down.
The house has other strange rooms (a giant mirror room being important to the plot).
The original owners are now ghosts haunting the house.
and again, I'm pretty sure I saw this on the sci-fi TV channel somewhere between 2002 and 2005.