When I was in high school, my sister invited a few friends over to watch the movie "The Fog" (this was back in the early 90's, so we're talking the old version of the movie). They set up in the living room and turned out all of the lights to enhance the experience. 2 girls, 1 dude and me were in there watching the movie.
Well, I had seen the movie several times and knew there was a scene where the fog is outside a glass window, a figure slides up to the glass, knocks on the window and slides back. Fortunately for me, we had a neighbor next door that had a really bright flood lamp that lit up our back sliding glass door that was conviently located right next to the TV... they had the TV turned up so loud that I was able to sneak out of the garage, make my way out of the house to the backyard and wait for the scene.
The scene came, I glided to the door, knocked on it, and slid back...
The commotion I heard was priceless. I heard a blood curdling scream and people running around. I fell down outside with laughter and it took me a minute to regain my composure. I walked back in to the house to find that my father was not amused. He was questioning why there was so much noise and I ended up getting a lecture. Come to find out, the dude was the one who screamed like a girl.