Action-heavy video games can dramatically improve your ability to pick and choose relevant visual information from a chaotic field - a skill known as "visual attention". When compared to their non-gaming peers, gamers excelled at tests designed to quantify their visual attention.
However, just plugging away at Farmville isn't enough. The games that give the benefit are "fast-paced, action based games that emphasized rapid responses to visual information and required divided attention."
Non-gamers who trained using games improved their visual attention scores, leading researchers to believe that games of this sort could be used for education, military training, and to help treat medical conditions like amblyopia, also known as lazy eye.
Research to be published in WIREs Cognitive Science