The Plimpton Stimulation Season 3, Episode 21 -  Aired May 10, 2010

The Plimpton Stimulation

The gang is surprised to hear Sheldon is having a female guest stay over. Although Sheldon's interest in his guest is purely academic, Dr. Elizabeth Plimpton invites a different kind of attention when she meets Leonard, Howard and Raj.

Rate this episode

Guest Stars: Judy Greer as Dr. Elizabeth Plimpton

Writers: Chuck Lorre (Story), Bill Prady (Story), Lee Aronsohn (Story), Steven Molaro (Teleplay), Jim Reynolds (Teleplay), Maria Ferrari (Teleplay)

Director: Mark Cendrowski

Viewers: 13.73 million Households Rating: 8.2/13 Adults 18-49 Rating: 5.3/13

Available on iTunes

Episode Notes

  • The title refers to Sheldon's guest, Dr. Elizabeth Plimpton, and the stimulating effect she has on the guys.

> Bazinga

When the guys are surprised to hear Sheldon will be having a female companion stay in his bedroom, they wonder whether he's kiding them. Sheldon tells Howard "A, I rarely kid. And B, when I do kid, you will know it by my use of the word Bazinga". When Howard asks if the two of them will be sleeping in the same bed, Sheldon tells him "Yes. Bazinga."

> Roommate Agreement

When Leonard wonders whether Sheldon's female guest is human, Sheldon reminds him that pets are banned under the roommate agreement, with the exception of service animals and, one day, cybernetically-enhanced helper monkeys.

Episode Quotes

Howard: Are you planning on kidnapping a woman?
Sheldon: Sarcasm?
Howard: Yes, but mixed with genuine concern.

Howard: I have a two-part question.
Sheldon: Go ahead.
Howard: A: Are you kidding? And B: Seriously, are you freaking kidding me?
Sheldon: A: I rarely kid, and B: when I do kid, you will know it by my use of the word "Bazinga".
Howard: So you're saying the two of you are going to be sleeping in the same bed?
Sheldon: Yes. Bazinga.

Leonard: Uh, sleep night. I mean, obviously, good night. I started to say sleep tight then I changed my mind in the middle. I swear to God, I'm smart.
Sheldon: Get it together, man.

Sheldon: Now listen, one of the great minds of the 21st century is about to play host to one of the other great minds of the 21st century. So pay attention. Years from now, my biographer might ask you about this event.
Leonard: Oh, I have so many things to tell your biographer.

Sheldon: Pee for Houston, pee for Austin.
Pee for the state my heart got lost in.
And shake twice for Texas.

News Stories

Title Date Posted
Episode 3.21 Ratings May 11, 2010

Last night's episode finished first in key demographics, coming second in total viewers.  Full story

CBS Announces Episode 3.21 April 13, 2010

CBS announces episode 3.21 to air May 10th. Judy Greer guest stars.  Full story


The guys are stunned when Sheldon informs them he will be having a female guest, Dr. Elizabeth Plimpton - a noted physicist, stay over. Sheldon quizzes Penny about the "female hygiene product" he bought for his guest, while Penny is just as puzzled as the guys at Sheldon having a female visitor.

As Sheldon welcomes Dr. Plimpton to the apartment, a nervous Leonard fears he made a fool of himself. After Sheldon shows Dr. Plimpton to her room and explains the apartment's emergency procedure, she goes to Leonard's room and starts flirting with him. The next morning, Sheldon wakes up to find a smiling Leonard and Elizabeth. When Penny comes over for a ride to work, she is introduced to Elizabeth and immediately picks up on what happened over night. Sheldon is shocked to hear that Leonard betrayed him.

At the cafeteria, Leonard is dropping hints about his enjoyable night, but the guys are not picking up his subtle clues. When Sheldon arrives with Dr. Plimpton, she immediately starts flirting with Raj. That night, Howard turns up at Raj's apartment for Halo night, but Raj tries to brush him off. When Howard finds Dr. Plimpton there, she invites him in for a "role-playing game". When Leonard arrives, she invites him in too. The guys consider the rare opportunity they've been presented with, but ultimately decide they don't want to see each other naked. Raj tricks Howard and Leonard into leaving the apartment, then continues his night with Elizabeth.

Later, Leonard tries to explain his amorous encounter to Penny, but she tells him he doesn't owe her an explanation. When Leonard persists in explaining it to Penny, his reasoning for his sexual encounter is "She let me.".