The game is what going out is all about. It is the process of getting into a girl's pants. You go to a club, hit on a girl, take her home. If you succeed doing that, you mastered "the game". It is what makes girls like you and fall for you, like your aura.
Doreen: Hey, you know Chris? I did him last night. Man, he knew how to master the game! It was crazy.
Kim: Yes, who did not fuck him? He even did Tina, the little hottie! He totally got game!!!