It seems that Games aren't the only thing that causes this 'Seasickness' that we have been talking about in certain threads.  The government (more aptly) calls this Simulator Sickness, and it looks as though they've done a few studies on it.
 
While the report I will quote is geared towards flight simulators and military pilots, I think the report can easily be adapted to gamers' use. They make the point a few times how VR Applications will be used by the general public, and compare their military findings with what they think would happen in the 'real world.'  Since 3d (esp. 1st person) games are kind of a virtual reality... I think the study is a good one to look at, at least for reference.
 
The entire report is very long, and can be found at:
http://www.cyberedge.com/4a7a.html if anyone was interested in looking at it.  But I will paraphrase some of the more interesting points, for those of you who do not care to read this fairly technical (but interesting and surprisingly easy to follow) report.
 
My comments are in [brackets], with more comments and sort of a plan of my experiments at the end.

- From studies of 10 Navy & Marine flight simulators, 20-40% of the pilots exhibited some signs of Simulator Sickness.  They theorize that since pilots are self-selected (people who are motion sickness prone don't choose to be pilots), a higher percent of the general population would have this Simulator Sickness problem in a VR environment.
 
- They think the problem has to do with something they are calling "Cue Conflict."  What this is, is basically your brain seeing things but you not feeling them, so your brain gets confused and makes you sick.  For example, if you are playing a racing sim, and you throttle forward, and the car looks like it is speeding up, so your brain thinks you should be speeding up, and you're not, there is a conflict in your brain, which it doesn't like, so it makes you sick.
 
- They think that since perceptual and perceptual-motor systems are modifiable; people can *learn* to get over Simulator Sickness [this is good news.. but I don't think the 'learning process' is going to be any fun] by a longer period of adaptation to the new environment.
 
- They found that a disruption in balance and coordination After being in the simulator happened with 60.4% of Air Force Pilots.  For 14.6% of the pilots, it lasted 30 minutes to 10 hours of being in the simulator.
 
- They found that pilots who experienced sickness the first few times they were in the simulator could rapidly adapt to the simulator, and experienced less sickness over time.  They are concerned, however, because reduced symptoms during immersion because of adaptation seemed to lead to higher levels of post-immersion symptoms.
 
- Chinese-born women (who had been in the US for less than 3 years) had a much higher susceptibility rate than did US-Born Caucasian women and African American women, whose results were the same.  They are not sure if this is environmental or genetic.  [although i would tend to think it would be environmental]
 
- They talk about technology factors that affect simulator sickness.  They identified Flicker, time lag, phosphor lag (the continued glowing of the phosphor on the CRT screen from one frame to the next), refresh rate, and update rate as potentially the most important aspects of a simulation system, but again noted that they are among the most difficult to measure, since each person perceives these at different points.
 
- Women are more susceptible to this problem than men.  [It seems I was wrong before, when I stated I didn't think so]  A researcher pointed out that this may be due to underreporting of susceptibility by men in self-reports, but added that research has shown hormonal effects (susceptibility may change during pregnancy and menstruation).  Other researchers noted that women exhibit larger fields of vision than men, which tend to result in increased incidence of simulator sickness.
 
- Two researchers claim that the ability to perform Mental Rotation (mentally rotating objects and recognizing objects when they are not in their usual orientations) is important for competent function and the reduction of motion sickness.
 
- Two researchers stated that a significant reduction in motion sickness occurs when a person lays on their back. They attributed this to restricted motion of the head.  [so - great.  if anyone sees a setup that lets me view the monitor, type, and control a joystick while laying on  my back, let me know.  ;)]
 
- Method of Movement (joystick, wheel, mouse, keyboard, whatever) may be associated with simulator sickness.  If you wouldn't normally move your hand forward to go forward, your proprioception vs. sight vs. what is relayed on the screen could cause conflict.  [this bothers me a *lot* when playing these types of games]
 
- Unusual maneuvers, such as abruptly freezing the simulation and "flying" backwards, should be avoided in the simulator.

A lot of these things are out of my control, as a player.  I cannot calibrate my mouse/gamepad to make the game correlate with it.  But who can?  Is it the game controller manufacturer?  Is it the video card manufacturer?  Is it the author of the graphical API (3dfx, microsoft)?  Is it the people who write the games?  Or is it a combination of some or all of the above?  Maybe someone with more technical knowledge can help answer these questions.
 
Obviously, the refresh rate has to do with the monitor manufacturer and the video card manufacturer.  Since I have a fairly good monitor (Viewsonic PS790 19") and video card (Matrox Mystique G200), I will see if they help my problem at all.  (my last instance of playing a 3D game was on a Mag DX15 Monitor with an ATI Mach 64.. so not the best setup)
 
I tried to download the "Thief: The Dark Project" demo like someone suggested, but it wouldn't work (I tried twice).  I have Rage, Incoming, and Toonstruck on some CDs that came with the video card... I will see about installing them and performing my tests on the least offensive of the three.
 
A "Natural Health" site [link no longer available]  suggested taking Ginger tablets to combat motion sickness.  While the military report stated that motion sickness was not the same as simulator sickness, it still may help the problem.  I'm going to the movies today, and will pick up a bottle of Ginger tablets (they suggest 2 450 milligram tablets 10 minutes before traveling) at the Natural Pantry to include in my trials. The site says that in a recent study (why the heck are those words not highlighted, with a pointer to the study??), ginger was more effective than Dramamine.
 
I will not include Dramamine in my Simulator Sickness study.  Mostly because it makes me fall asleep about 30 minutes after taking it, which is handy for long plane rides, but not so handy when you're wanting to play games.

If anyone else has any suggestions (I'm looking for physical suggestions ... sit this far from the monitor... make sure your feet are on the ground.. or off the ground ... use your gamepad, not your mouse.. or vice versa... touch your right earlobe with your left pinky finger while you are playing... something like that), I would look forward to hearing them, and perhaps including them in my experiments.

When I told my bridge partner, the intellectual/retired newspaper editor about my investigative journalism/experiments, I thought he'd be proud of me.  Instead, he laughed.  

He said, "What I think you ought to do, is get a big Rubbermaid trash can, sit it next to you, and play DOOM until you puke, and see if that solves the problem."  I told him that I have been prone to motion sickness since I was a very little girl and threw up bologna sandwich all over the back seat of my mother's white ford station wagon (I must have been three, and I swore I would *never* eat another bologna sandwich after that, and I haven't), so I didn't think that would help.
 
I honestly and sincerely want to get over this.  I have gotten over other 'problems' before (an absolutely paralyzing fear of needles, to name one), so I am confident that if I am not able to completely solve this problem, at least I will be able to lessen the effects of it.
 
The rest, of course, will need to come from technology & developers of that technology.  I'll work on convincing them later.  :)