If you guys remember Sodalis did a report on this a whgile back. He found that everyone is a gamer to some extent.
His main thesis was that gaming is an integral part of growing up, and as people grow, they take gmaing into the real world and use it in their everyday lives.
Remember when you were young, and played war games with little green soldiers? How about GI Joe? Those wierd voices you would make while trying to immitate the person you were holding in your hand... whether snake eyes, or storm shadow, or Duke... or even Cobra Commander...
Girls RP too- but in a different way. they play house, pretending to be mothers and caretakers. Making food out of leaves and grass, mud and sticks.
If you read his report, you would know that it was truncated- chopped. He needed 10 pages- but his final report was somehwere along the lines of 30. He hacked out a lot of good stuff:
Boys and girls both RP- boys are more active in their imagination- focusing on what people "do", while girls are more elaborate in theirs- focusing mostly on details and "fluff".
Taking this further into Sociological viewpoint, Goffman states that we all wear masks. In every situation that we find ourselves in, we observe and calculate out which personality would get us the best results (based on the reaction we are looking for) and we wear that mask- a suit that covers our entire personality.