This happened to me in Elgin, during my tour at RAF Lossiemouth.
I was living off base with two friends. They'd gone to bed but I stayed up a little to read my book The Manitou by Graham Masterton. I was enjoying the story so much I forget the time.
During one gap in my reading, I glanced at the clock - S~~t! It's 3:00 am, I'd better go to bed - I thought. Putting the book on the table, I went to my room to try to get a few hours sleep.
I was dozing off, when I heard a tapping on the window. It's late, I's been reading a thrilling horror story and now there is a tapping on my window. In the darkness of my room, logic evaporated. The window was on the first floor and the nearest lamppost was well out of reach of the window - to my imagination that didn't matter.