Hi, I'm looking for a book I had when I was a little bit younger. It was a chapter book, and it was about a dad and two daughters who were going to their grandmother's house to get a doll-house, but on the way there is a storm and they end up going to this really crazy-looking house that turns out to be some sort of weird museum....or the home of a magician...or both?

Anyways, there is a guy dressed up as a giant rabbit, some of the museum artifacts get stolen, and the magician, who is currently working on creating artificial rainclouds in a bathtub in the basement, uses a robotic sniffing spider to track down the culprit.

I really don't remember much more than that...