Researchers at the University of Rochester have shown that people who played action video games for a few hours a day over the course of a month improved by about 20 percent in their ability to identify letters presented in clutter - a visual acuity test similar to ones used in regular ophthalmology clinics.

In essence, playing video game improves your bottom line on a standard eye chart.
...
The experimental group played Unreal Tournament, a first-person shoot-'em-up action game, for roughly an hour a day. The control group played Tetris, a game equally demanding in terms of motor control, but visually less complex.

After about a month of near-daily gaming, the Tetris players showed no improvement on the test, but the Unreal Tournament players could tell which way the "T" was pointing much more easily than they had just a month earlier.

Link

First-person shooters make me nauseous. And i pretty much suck at Tetris. I suspect that at some point, i also stop breathing when i play video games. This prolly contributes to the headaches and nausea. So, i can't improve my motor skills or my eyesight. This blows.