The Separation Oscillation
Season 9, Ep. 2
As Leonard and Penny struggle with the revelation he kissed another woman, Leonard goes to meet the woman in question. Elsewhere, Sheldon films an episode of Fun with Flags alone following his break-up with Amy.Meanwhile, Bernadette is uncomfortable with the fact she's known about Leonard's kiss for two years.
First Aired: September 28, 2015.
PREMIERE: The Matrimonial Momentum
Season 9, Ep. 1
Penny and Leonard deal with Leonard's confession on the way down the aisle while Sheldon struggles to understand Amy's decision to take a step back from their relationship.
First Aired: September 21, 2015.
FINALE: The Commitment Determination
Season 8, Ep. 24
Leonard and Penny are pressured to set a wedding date by Sheldon, whose relationship with Amy has taken an interesting turn.
First Aired: May 7, 2015
The Maternal Combustion
Season 8, Ep. 23
Sheldon's and Leonard's mothers finally come face to face and their personalities collide.
First Aired: April 30, 2015.
The Graduation Transmission
Season 8, Ep. 22
Leonard and Penny are headed to New Jersey, where Leonard is scheduled to give a high school commencement speech. Raj's father is tired of his reckless spending habits.
First Aired: April 23, 2015.
The Communication Deterioration
Season 8, Ep. 21
The guys clash about a message that could be used for contacting aliens.
First Aired: April 16, 2015.
The Fortification Implementation
Season 8, Ep. 20
When Sheldon and Amy build a blanket fort, they come to major crossroads in their relationship. Also, Wolowitz meets the half-brother he never knew he had.
First Aired: April 9, 2015.
The Skywalker Incursion
Season 8, Ep. 19
While on their way to UC Berkeley, Sheldon and Leonard take a detour in hope of meeting an idol.
First Aired: April 2, 2015.
The Leftover Thermalization
Season 8, Ep. 18
A magazine article only credits Sheldon in an article about a paper he co-wrote with Leonard.
First Aired: March 12, 2015.
The Colonization Application
Season 8, Ep. 17
Amy finds out that Sheldon applied for a one-way mission to colonize Mars.
First Aired: March 05, 2015.
The Intimacy Acceleration
Season 8, Ep. 16
Penny and Sheldon design an experiment -- as a joke -- to make participants fall in love.
First Aired: February 26, 2015.
The Comic Book Store Regeneration
Season 8, Ep. 15
Amid the excitement of Stuart reopening his comic-book store, Howard gets some unsettling news; and after teaching Sheldon how to "let it go," Penny doesn't practice what she preaches when she learns something maddening about Amy.
First Aired: February 19, 2015.
The Troll Manifestation
Season 8, Ep. 14
An online troll rips Leonard and Sheldon's published physics paper, so the guys rally to defend the two and expose the bully, while a girls night out leads to Penny, Amy and Bernadette dishing about embarrassing past events.
First Aired: February 5, 2015.
The Anxiety Optimization
Season 8, Ep. 13
Sheldon becomes concerned that his cushy lifestyle is impacting his professional progress and keeping him from achieving scientific renown, so he asks the gang to make life more difficult for him. Meanwhile, Howard invents an unflattering game about Raj.
First Aired: January 29, 2015.
The Space Probe Disintegration
Season 8, Ep. 12
While Raj eagerly awaits data from a space probe in which he was involved, Howard keeps distracting him. Later, dress shopping with Penny and Amy doesn't exactly prove to be a good fit for Leonard and Sheldon.
First Aired: January 8, 2015.
The Clean Room Infiltration
Season 8, Ep. 11
On Christmas Eve, Amy plans a traditional Victorian dinner, while Raj, Leonard and Howard scramble to remove a pigeon that flew into the clean room at the university. To prove a point to Amy, a Scrooge-like Sheldon buys her the worst possible gift.
First Aired: December 11, 2014.
The Champagne Reflection
Season 8, Ep. 10
It's a banner day for Sheldon as he bids a sad farewell to his "Fun With Flags" podcast. Meanwhile, Leonard, Howard and Raj probe a late professor's research in search of some hidden significance; and Bernadette is surprised when Penny reveals how her co-workers really feel about her.
First Aired: November 20, 2014
The Septum Deviation
Season 8, Ep. 9
Leonard needs surgery for a deviated septum, and Sheldon gets his nose out of joint because he feels an operation is too dangerous and that his roommate may not make it out alive. Meanwhile, a distraught Raj learns his parents have divorced on the eve of their 40th anniversary.
First Aired: November 13, 2014
The Prom Equivalency
Season 8, Ep. 8
Amy and Bernadette organize a prom to be held atop the guys' apartment complex, but Sheldon is leery of all the prom pomp, circumstance and romancing that goes with it.
First Aired: Novemeber 6, 2014
The Misinterpretation Agitation
Season 8, Ep. 7
Penny's flirtatious sales pitch leaves a doctor-client smitten and the guys must pitch in to help her deal with him, while, Bernadette and Amy debate whether female scientists ought to play the sexuality card.
First Aired: October 30, 2014
The Expedition Approximation
Season 8, Ep. 6
Sheldon and Raj undertake an underground research expedition that turns into a test of how long before they get under each other's skin. Meanwhile, Leonard and Penny argue about money, and go to Wolowitz and Bernadette for advice.
First Aired: October 20, 2014.
The Focus Attenuation
Season 8, Ep. 5
With the girls away in Vegas for the weekend, the guys try to invent “the next big thing,” but only come up with new ways to procrastinate.
First Aired: October 13, 2014.
The Hook-Up Reverberation
Season 8, Ep. 4
Raj's girlfriend, Emily, gives Penny the cold shoulder after he reveals some info about their past history; and the guys contemplate buying into Stuart's comic-book emporium.
First Aired: October 6, 2014.
The First Pitch Insufficiency
Season 8, Ep. 3
A nervous Wolowitz is thrown for a loop when NASA asks him to toss out the first pitch at a Los Angeles Angels baseball game. Meanwhile, Sheldon brags that he and Amy are a better couple than Leonard and Penny, so they set out to prove he's way off base.
First Aired: September 29, 2014.
READ: 'The Big Bang Theory' couples take on Major League Baseball and one another in an all-new episode
The Junior Professor Solution
Season 8, Ep. 2
Sheldon is ordered to teach a class, and the gang is surprised when Howard signs up to take it; and tensions between Penny and Bernadette afford Amy an opportunity to play one against the other.
First Aired: September 22, 2014.