I had one experience several years ago where some friends and I went to shoot airsoft guns at each other one night. There were about 9 or 10 of us and we decided to play at this church/school that one of my friends did maintenance for. We divides into two teams, went to opposite sides of the property, and waited for the agreed time to start. My team (about four of us) started on the church side which also doubled as the schools basketball court (crazy, I know). Off to one side of the court were some mats rolled up and standing veritcally next to some office doors. One of my friends and I noticed one of the doors open and a dark figure creeping from the doorway to hide behind the mats. I alerted my team to surround the mats. I never took my eyes from that area but when we looked, no one was there. I thought it was weird but I was too focused on the game to give it a whole lot of thought. After the game, I talked with my friend who worked there and he said that there had been some weird occurrences there, like people see other people in reflections while no one else is around or hearing their name called by a voice they never heard before.