Day 20 of Halloween Countdown is heeeerrrrrreeeee!
Having had a similar experience as a child (true story) this scene from Poltergeist has always been my favorite.
I used to get up very early in the morning and sit in front of the TV, very close to the screen. I did not turn the TV on. It was off, but in the reflection of the screen I could see myself, the room and furniture behind me, and people moving about the living room. If I turned around there was no one there, just an empty room.
So I would sit staring for an hour or two at the TV screen and the people in my living room until my Mom woke up and told me to turn it on.
I told her I could see people. I was probably four or five.
She's probably glad I'm not crazy.