One of the greatest tales had to do with "ghost eyes" coming from local
woods.  I immediately knew what this really was and showed the kids-
phosphorescent fungus that glows in the dark.  For weeks the kids thought
there were eyes staring at them.

Another time a family kept seeing shadows.  This turned out to be coming
from a mouse.  When it would cross a certain path and the light would hit it
in a certain way, there would be a large shadow and only for an instant
because mice of course move fast.

The greatest challenge came from a "mist" in the basement.  Students and
parents claimed the mist had a "personality" and would move all around
without air and for no reason.  After a lot of careful examination, the mist
turned out not only to be formed by artificial causes (a water heater in the
basement was creating it due to a malfunction), but the movement was natural
as well (even though the basement looked closed, there were still plenty of
cracks allowing air to circulate).

There were other investigations over time, but the aforementioned are some
of the most interesting stories.  The most common explanation in 95% of my
investigations turned out to be a small animal loose in the house, most
commonly mice, rats, coons and even a snake or two.  A rat can cause a
tremendous noise that resembles footsteps especially as it travels up and
down stair steps.

I think one of the things I like about the "Ghosthunters" show on Sy-Fy is
the fact that they never really find anything and 99% of what they encounter
is explainable, even those things they act like are not.  They often debunk
their own experiences either in the same episode or in future ones.

Now for several of my most sinister investigations.  I had students over the
years claim to see ghosts.  I would show up at the home and see nothing, but
the students would claim to see a ghost while I was standing there
conversing with them.  Unfortunately, and you'll see why I use this term in
a minute, most of this was explained but not in the way I wanted by a type
of undiagnosed schizophrenia that was later diagnosed.  There are apparently
many variations of the disease, with one type causing the illusion of ghosts
and apparitions.  Treatment is usually mild through medication.
Unfortunately, I suspect that most people who continue to see ghosts
throughout their lives have undiagnosed forms of the illness.  This doesn't
seem to cause apparent harm to them or others other than induced stress
(scared when they see something) and sometimes physical injury when they try
to "escape".  Do I think that everyone seeing a ghost is schizophrenic?  No,
but there is a possibility that's all.

My greatest gripe with the ghost phenomenon is that there doesn't seem to be
any true way to test it.  If such apparitions do occur, why can it not be
repeated and why aren't there reliable detections of ghosts with
instrumentation?  Technically, such phenomena doesn't fall under the
scientific method and is largely dismissed by science.  Not to change the
topic, but the same holds true for UFO's.

Hope I have shed some light on this popular topic especially with recent
movies and Halloween.