I'm just finishing reading this to my six-year-old (the nine yearold is listening, despite having read it twice already)and we all love it so much that they can even been torn away from The Simpsons! If you haven't dsicovered Ibbotson yet, start with this one, or The Secret of Platform 13 (which is astoundingly like Harry Potter, but long before Harry Potter was written).
Oliver, an orphan, unwillingly inherits Helton Hall from his dreary relations, never guessing that the evil Fulton and Freida Snodde Brittle (family motto: I set my foot upon my enemies)want it so badly they pay an agency to send them the most horrible ghosts on their books. Luckily, the Shriekers (not only violent, but snobs) get sent to some kind nuns by mistake, and Oliver is sent the lovely, gentle Wilkinson family. The Wilkinsons, who have been camping in a London knicker shop ever since a bomb fell on their own home, have adopted a little girl ghost called Adopta, and she becomes Oliver's special friend. But the evil Snodde-Brittles are furious when, instead of dying of asthma and terror, Oliver loves his new guests...and The Shriekers, equally furious, are coming to Helton too.
Funny, thrilling and moving. We all adored it.