With a hat tip to Raph Koster … the Pew Research center has put out their study noting more adults than kids play: 

“More than half of American adults age 18 and older (53%) play video games … “

The main grouping of gamers seems to hover around the ages of 18 and 29 with a full 81% of gamers.

The article is full of other great quotes, but I must point out this one:

“Computers are the most popular equipment for video game play; consoles are the favorite gaming hardware among the youngest players.”

Ahem … PC gaming rules.