The Maternal Congruence — [s3e11]

: Leonard is terrified that his mother will disapprove of Penny, whom Sheldon describes as having a career defined mostly by memorizing the Cheesecake Factory menu.

: This episode is notable for being the first of only two in the series where a main character— Raj Koothrappali —appears but has no speaking lines . [S3E11] The Maternal Congruence

: In the opening scene, the gang is watching the 1966 How the Grinch Stole Christmas! . Funnily enough, guest star Christine Baranski also appeared in the 2000 live-action film adaptation. : Leonard is terrified that his mother will