The Margaret Williams Theatre at New Jersey City University is supposedly haunted. I worked there for several years and can confirm weird things happening. Mostly sounds.

For example, there were many times I would be alone in the office backstage and no one else would be in the theater (we were very strict about having unauthorized people in theater) and I would hear footsteps crossing the stage. (there was an overhead microphone wired into a speaker box in the office so we could hear what was going on onstage and in the house.)

Sometimes we would hear some of the doors rattle. And a few of these doors had no access to the main building. Think loading dock type area with no access to the public. Doors could only be opened from the inside like an emergency exit, so they led from the theater directly outside.