Do you remember that episode of Smallville where the Luthur's plant didn't have a third floor?
I was at a hospital in London last week and strangely enough, I noticed that there was no third floor when I decided to take the stairs, where the door should have ben it was sealed off. Then on the lift, i noticed there wasn't any button for the third floor so made me think of that episode in Smallville!
Another thing is, after i told my bf about it, he said that he read in a Steven King book that hotels don't have a 13th floor so that you don't have to be staying in room 13 on the 13th floor or something. Weird.