Extreme gamers, which represent 4 percent of the total U.S. gaming population, spend 48.5 hours a week playing games, according to a new report from The NPD Group. Overall, U.S. gamers spend 13 hours per week playing games, up from 12.3 hours in 2009. When looking at the number of hours gamers spend per week playing video games, hours spent playing both console and PC games showed a marked increase over last year's study,