If you get sick from playing FPS type games, the secret is to sit back further from your monitor so your eyes can see stuff in your room. Motion sickness is basically caused because your eyes and your sense of balance are sending mixed signals to your brain. Your eyes are telling your brain that you just made a right turn, but your inner ear is telling your brain you haven´t moved. If you sit further away from the monitor, your eyes are better able to realize that you aren´t really moving.