The Maternal Congruence

"The Maternal Congruence" is the eleventh episode of the third season of the CBS sitcom, The Big Bang Theory. This episode first aired on December 14, 2009.

Summary
Leonard's mother, Dr. Beverly Hofstadter, has a return visit for Christmas announcing that she is divorcing Leonard's father and bonds with Penny at the Cheesecake Factory bar.

Extended Plot
The episode begins with Penny and Leonard decorating Leonard's Christmas tree. After being asked to contribute, Sheldon gives them a bust of Sir Issac Newton to hang on the tree partially since he was born on Christmas day and Jesus was not.

A visit from Leonard's mother, Dr. Beverly Hofstadter (Christine Baranski), delights Sheldon and horrifies Leonard. Penny is upset because Leonard didn't mention his mother's visit to her, but that is nothing compared to when Leonard learns that Sheldon knows more about his own mother than Leonard does.

Leonard learns about his parents' pending divorce, his mother's surgery, and the death of his dog all after Sheldon had known. Beverly questions Howard and Raj about their ersatz homosexual relationship (alluding to her last visit in The Maternal Capacitance) and Howard tries to tell Leonard's mother that he has a girlfriend, but she doesn't seem to believe him. He tells Leonard to tell his mother that he has a girlfriend, but Leonard responds, "I have no idea what you're talking about." Penny and Beverly go out drinking at the Cheesecake Factory and get terribly drunk. Penny tells her about her relationship with Leonard and Beverly tells her about her interest in the busboy, and when they get back to the apartment, a drunk Beverly scolds Leonard for not telling her that he was in a relationship with Penny. Leonard then confronts her about not telling him about her surgery, divorce and his dog's death and he wants a closer mother and son relationship, so Beverly hugs him. After Leonard is gone, Beverly kisses Sheldon much to Penny's horror. The next day, Penny and Beverly are hung-over and Leonard and Sheldon are taking Beverly to the airport. Beverly asks Leonard to take care of Penny and hopes Sheldon will forgive her for her actions the previous night, however, they all decide to keep it a secret from Leonard. Besides, she concludes that she would rather have had the busboy.

Critics
"[It's] worth saying that the story is a good one in theory. Beverly is a good character, who acts the part really well. The idea of Leonard’s mother being cold and logical and thus Sheldon being like a surrogate parent to Leonard is  interesting. It’s as if Leonard couldn't fit in in the real world and found comfort with a best friend who replicated his familial experience...Beverly kissing Sheldon was also a nice moment. Partly out of the novelty of seeing Sheldon’s first kiss and partly because it was correctly blown off...It would have been nice to see Penny comforting Leonard. I don’t think they show enough physical affection to be a convincing couple and this would have been a nice time to show some. It’s like The Big Bang Theory and I are an old married couple and we have the same argument every week." - The TV Critic's Review

Quotes

 * Sheldon: I found the Grinch to be a relatable and engaging character, and I was really with him right up the point that he succumbed to social convention and returned the presents and saved Christmas. What a buzzkill that was.
 * Leonard: When we watch Frosty the Snowman, he roots for the sun.
 * Sheldon: Excuse me, but the sun is essential for all life on Earth. Frosty is merely a bit of frozen supernatural ephemera and a stolen hat—a crime, by the way, for which he is never brought to account.
 * Leonard: (singing) Fa-la-la-la la-la-la-la!

Trivia

 * Leonard has a Sideshow Collectibles Aragorn Legendary Scale Bust with the shattered Narsil in his room. Likewise, Sheldon has a Sideshow Collectibles Legolas Legendary Scale Bust with iconic dual long knives in his room, clearly seen in "The Plimpton Stimulation".
 * During the bar scene involving Penny and Beverly, after they ask for another round, an over-the-shoulder shot of Penny shows Beverly's glass nearly empty. It then switches to a over-the-shoulder shot of Beverly. A second later after it changes back to the shot of Penny, Beverly's glass is full. It switches back again, and after a 3rd OTS shot of Penny, it shows Beverly's glass back to how it originally was.
 * Leonard says, "Mmm, in my family, holidays weren’t so much celebrated as studied for their anthropologicaland psychologicalimplications on human society." Likewise, his birthdays weren't celebrated either, as revealed in "The Peanut Reaction".
 * The show begins with Leonard, Penny and Sheldon watching How the Grinch Stole Christmas. Christine Baranski, who appeared later in the episode as Beverly, had a role in the 2000 remake of the animated movie.