"The Cushion Saturation"

A paintball game leads to a fight between Penny and Sheldon, but also for a romance between Wolowitz and Leslie!

"The Maternal Capacitance"

Leonard's mother, Mrs. Hofstadter (Christine Branksi) comes into town and she ends up being exactly like Sheldon.

"The Financial Permeability"

Sheldon lends Penny some money which makes Leonard go and try and collect some money from her ex-boyfriend Kurt for her.

"The Friendship Algorithm"

In order to get time on the super computer at work that he needs for his experiment, Sheldon must befriend Kripke who is in charge of the device.

"The Killer Robot Instability"

When Penny's comments about Wolowitz's love life sends him into depression, the boys are about to lose their most important teammate in an upcoming robot fighting competition.

"The Bath Item Gift Hypothesis"

It's Christmas time and Sheldon is annoying everyone with his theories on gift giving etiquette. Meanwhile, Leonard gets jealous when Penny stars dating one of his handsome co-workers.

"The Vartabedian Conundrum"

When Sheldon and Penny convince Leonard that Stephanie has moved in, Sheldon tries to slow the relationship down.

"The White Asparagus Triangulation"

Sheldon tries to secure Leonard's relationship with Stephanie and sets up a scenario where Leonard can prove he's the alpha male.

"The Lizard-Spock Expansion"

Wolowitz thinks he's found his soul mate, Dr. Stephanie Barnett (Sara Rue), until she meets Leonard. Wolowitz lets Stephanie drive the Mars rover, which gets stuck in a ditch.

"The Panty Piñata Polarization"

When Penny's cable goes out, she starts going over the guys' apartment to watch America's Next Top Model. However, after violating some of Sheldon's arbitrary rules, he bands her from coming over.

TBBT Quotes

Sheldon: Are you still mad about the sperm bank?
Leonard: No!
Sheldon: Do you want to hear an interesting thing about stairs?
Leonard: Not really.
Sheldon: If the height of a single step is off by as little as two millimeters most people will trip.
Leonard: I don't care—two millimeters?! That doesn't seem right.
Sheldon: No, it's true! I did a series of experiments when I was twelve; my father broke his clavicle.

Penny, there's only one cookie with something in the middle that solves life's problems, and that's an Oreo. Or a Nutter Butter, if you're in a pinch.

Sheldon