I let my best friend believe his apartment was haunted for 8 months. It was brought about by a serendipitous kick to his door at the very moment he unlocked it and turned the handle. It caused the door to go flying, so from his perspective someone (or someTHING) forcefully yanked the door open from inside his apartment. Spooky, huh? I played along and even took it a step further and knocked over a globe that was on an end table right next to him. I inched it and inched it closer to the edge to where it was barely on the table top and when my friend got up and his couch nudged against the table it knocked over the object. Again, from his perspective it appeared like the globe "just flew" off the table.
Seriously guys, explaining something away by attributing it to ghosts is the same as attributing it to unicorns. Both have equal amounts of evidence.