Nothing much happened... I'm an Atheist and I don't believe in the paranormal. There is always a logical answer for everything... right? Here is my story.
I was sitting by the computer. This was about two weeks after my dad had passed away. My mother was downstairs, getting ready to go to bed. I could hear her rocking about in the bathroom through the music in my headphones. Some minutes passed by and I felt a hand touch my shoulder, like real physical weight being put on my shoulder. A whole palm. Not pushing, just resting there. My parents always did this so that I didn't get scared when they announced that they were going to bed.
I was in the middle of a bossfight in WoW, so I couldn't turn around at the same moment the hand was put on my shoulder. After five to ten seconds, I removed my headphones, spun my chair around, and got ready to rise up and give my mother a good night hug. But the problem was that no one was in the room, and my door was still closed... After a few seconds, I could still hear my mother downstairs. I went out in the hallway and shouted to her, asking if she was in my room a few seconds ago, and got a very confused, "No?" as an answer. I didn't debate this with her further.
When I came back to my room I just sat down and stared into nothingness. I knew someone had put their hand on my shoulder, but no one was around. I could still feel the touch. This episode has haunted me for five years now and I can remember that very moment perfectly. I still can't find an answer for what happened.