The social group or Team Leonard was formed when Leonard befriended Howard and Raj, as told in retrospect in "The Staircase Implementation" (3.22). As Sheldon was living with Leonard, Sheldon constantly butted in when the three were hanging out and he quickly became a member of the group. He later established himself as the group's leader and comic relief although no one agreed that he was either. Even though Sheldon is not the leader of the group. Stuart was invited by Raj into the group in "The Decoupling Fluctuation" (6.02) after Howard went to space,