The founder and original Artistic Director would haunt the Mainstage theatre, appearing in his favorite balcony seat in his signature white tux every opening night performance. Several actors reported seeing him from the stage. The performance space had major renovations done in the 90s (gutted and entirely redone), and once the renovations were complete, the current Artistic Director took a portrait of the founder through the new theatre, showing him every nook and cranny that had been changed. The ghost hasn't been seen since - we like to think he's pleased with what we're doing.
On a darker note, the building our theatre is in was built in the 1830s, and during the Civil War was a church. The hotel across the street was being used as a hospital. Because churches and hospitals could not be entered by combatant soldiers, they were safe houses. The confederate soldiers in charge of the buildings took advantage of this by stockpiling supplies, weapons, and ammunition in the top floors of the hospitals. An underground tunnel connected the hospital to the church, so soldiers could smuggle guns from the hospital through the tunnel and out the church. When the Union soldiers figured out what was going on, they invaded the church, found the tunnel, and shot dead the two soldiers they found in the tunnel. The two soldiers still haunt that tunnel.
Since the theatre has been in existence, people have known about the tunnel ghosts. Ernst Borgnine and Gregory Peck both had ghostly encounters while working at the theatre, and countless technicians working overnight change-overs have reported hearing screams and thumps coming from the room with the tunnel. In the 90s the city did road work on the road above the tunnel, causing the middle of the tunnel to cave in, separating the ghosts (we believe), making them even more pissed off (we know). When we were having the remodeling overhaul, three construction workers were taking their meal break at 3am in the room with the mouth of the tunnel. All at the same time, without saying anything or looking at each other, all three men ran from the room as fast as they could. Our Artistic Director had to come to the theatre in his pajamas, go fetch the men's lunch boxes, and give them their severance pay on the spot, as all three men refused to ever set foot in our theatre again. The hotel has sealed off their side of the tunnel, but ours is still open - we use it to store extra cyc lights and lamps.