The Harry Potter exhibition is a traveling road show of original props and costumes from the HP movies. It is built on a 10,000 square foot set and is currently in Seattle, having been in Chicago, Boston and Ontario. The organizer plans to run the exhibition for five years and visit 10 cities around the world. It costs $ 30 per head for adults and $ 28 per head for kids 6-15.
It is well worth it. You have to make reservations, and groups are allowed in at 15 minute intervals. The wife and I took two of our grandkids to see it this weekend. They follow the Disneyland school of crowd/line management, and it flows pretty steadily through the exhibit. We were not rushed, saw everything we wanted to and were done in an hour.
The biggest surprise to me is that from looking at the costumes, Emma Watson, who played Hermione, is actually a tiny thing, not more than five feet tall. She seemed taller in the movies.
http://www.harrypotterexhibition.com/Default.aspx