These experiences happened on my previous company. It is a hardware-building materials company situated on a warehouse type 2-storey building.
Being an IT always gets me into abnormal working schedules; coming to the office much earlier than the rest of the employees, going home late, spent overtimes up to the wee hours, and even some couple of overnights.
Ever since I worked with this company (I was one of the pioneers then), me and other fellow employees experienced some paranormal occurrences around; like eerie sounds, banging of some things, sighting of a shadow, bare-foot prints, and other stuff.
One night, me and some programmer visitors had to stay overnight to update the servers. We went to the other office to fetch the new server units, and by the time we came back the building was already closed, most of the lights were off, and most of the employees had already gone. We were at the doorsteps, when we saw one female employee on the stairs heading towards the office room, so we hurriedly followed her, as to ask her open up the doors because we were bringing some equipment which were a bit heavy. By the time we reached the office door, no one was around and the doors are closed. We called, but nobody really answered. We called out the guards, to check and verified that everybody has already left. All of us were looking at each other wondering, who is she? Who was that then? Where did she just go? We were just steps away from her. That night in the office, we didn't sleep well, partly scared especially my visitors, so we just had that one computer volumed-up its mp3s.
Another incident was that I came very early. After some time, still few people were around, I was chatting with one of the janitors when we noticed that somebody was sitting in one of the displayed couches in the showroom. As we were approaching, we could clearly see him-sideways, and he was making gestures as if talking on his mobile phone; so the two of us assume that maybe it's one of our boss, who also comes early and sometimes sits around the couches talking to his associates. We're just some steps away when we had the shock of our lives, we saw blood dripping down his head, his face pale-dead! And it was clear that it was not our boss. I kept my self from terrifying as much as I could but the janitor just ran down the stairs as if she jumped all of the steps in one leap. We kept it for ourselves and waited for the other employees to arrive, then when we went back upstairs, obviously nobody was there in the couch. Later, I learned that he was a worker who fell down from the ceiling and broke his head and later died in a hospital. Some other employees also sees him around the building, particularly upstairs in the showroom. Every February, there would really be some strange occurrences, as it was the month when he died.
One little funny incident, it was Sunday and office is closed. Me and an electrician were laying network cable downstairs, and there were other people around since the showroom is regularly open. A customer called, and she said she was answered through our operator and it was a child's voice. How could it be possible for the operator to answer when the office is closed, and worst is that of a child's voice?! She even redialed, and still it was answered but all she heard this time was breathing, deep breathing. Later on that day, she really did came to the store for some urgent inquiries and confronts us. We checked, and the office is closed. And on the guards' log book, nobody went upstairs into the office that morning. Most horrifying was in the next day, we told the operator and when she checked her logs on the her machine, there really was a call (2 calls) answered.
Thank you for reading, until next time.