When I was young my grandma came over to our house to babysit me one night. Nothing unusual happened the whole night. But when my mom got home she checked the answering machine, and there was a message a few minutes long. The message was just my grandmother’s and my voice laughing hysterically for the whole message.
Like I said the night was normal, and there wasn’t a moment when the phone rang, or laughed hysterically for minutes on end.