The "poltergeist" incident happened when I was about 17. So about 20 years ago. My friend Derrick and I went out to a little get together one Friday night, and Derricks pregnant wife Cathy stayed home at their apartment with four or five of her girlfriends.
While we were gone they played with a Ouija board, and when Derrick and I returned it was "paranormal" chaos and panic to make a long story short. Hallmarks of a "poltergeist" incident were present. Objects flying around and electrical oddities mostly. Stuff was everywhere. It was like a tornado went through. It took Derrick and I awhile to clean it all up later that night. I myself saw a notebook fly across the room toward us as we entered the apartment. There was no one there to throw it. There were no open windows for wind. No fans. I saw the lights and appliances going on and off. It was sublime.
A couple of the girls had ran off to get help, but none of the neighbors were home. Some of the girls were huddled in the bedroom closet with Cathy, screaming and crying. IIRC correctly one had locked herself in the bathroom.
I chalked it up to demons at the time. I was Christian at the time and I did my Christian duty as I saw it and said some prayers with Cathy and Derrick. It seemed to work...or at least help a bit. People calmed down and things stopped happening. Although there were a few minor incidents over the next couple of weeks. All centered on Cathy. She had nightmares for a long time.
Cathy was the focal point. When they were playing with the Ouija board, the girls thought they were talking to a benevolent spirit. But through the ideomotor effect and the Ouija board "it" told Carol it was going to kill her baby. They freaked out. Big time. That's when things started happening.
The unconscious psi, amplified by the fear and belief of the girls produced those effects. Most likely it was Cathy alone, although it's conceivable that the psi of the other girls contributed. Either that or a genuine demon/poltergeist did. Or both. As one of the witnesses to the events I don't have the luxury of writing it all off as delusion or tricky, fraud, etc, etc.
And this is not even all of the weird things I've experienced.