The Big Bang Theory

After driving to Vegas to get married, Penny struggles with Leonard's confession, in the ninth season premiere.

Leonard confronts the woman he kissed on the North Sea, while Sheldon tries to retaliate after his breakup with Amy, using Fun with Flags.

The guys surprise Leonard with a belated bachelor party weekend; the girls force Penny to tell her family that she eloped with Leonard.

When Sheldon learns of a change in his living arrangements, he decides to revert back to a simpler time before he met Leonard or Penny.

When the guys take fencing lessons from Barry Kripke, Sheldon finds himself in an awkward position when Kripke expresses interest in Amy.

In the midst of a nationwide helium shortage, Leonard and Sheldon buy helium on the black market in order to complete an experiment.

Leonard & Penny are shocked to learn that Sheldon had an engagement ring for Amy; Howard & Bernadette disagree over remodeling their home.

With Amy out on a date with a mystery man, Sheldon enlists the help of Howard and Raj to find a new girlfriend by posting online.

Howard reluctantly agrees to volunteer at the soup kitchen; Sheldon and Amy spend Thanksgiving together as friends.

Sheldon has a revelation after desperately wrestling with a song stuck in his head; Amy invites Dave over for dinner.

After five years of dating, Sheldon and Amy spend their first night together; Bob Newhart returns as Sheldon's Obi-Wan to advise him.

Penny gets more than she bargained for when Leonard meets with a psychiatrist on her behalf; Stuart moves out of Howard & Bernadette's home.

After having to deal with Sheldon being sick, Leonard, Penny and the gang try to treat themselves to a Sheldon free weekend.

Sheldon's thrilled when his Meemaw comes to visit, but his excitement quickly fades when she butts heads with Amy; Raj meets a new girl.

Sheldon and Amy host a live episode of Fun with Flags for Valentine's Day; Raj is torn between Emily and the new girl he met.

When the gang finds out about Bernadette’s pregnancy, they celebrate by singing karaoke.

After nine years together, the gang finally celebrates Sheldon's birthday with a few special guests, on the 200th episode.

Leonard, Sheldon, and Wolowitz run into problems when they file for a patent for their infinite persistence gyroscope.

Amy is shocked at a revelation from Sheldon after she buys him a new laptop. Raj sells out Leonard and Howard after they lie to their wives.

Sheldon spills a secret of Leonard's when they take a weekend cabin trip with Penny and Amy. Raj goes overboard with buying pregnancy gifts.

When a small argument between Leonard and Sheldon erupts into a heated fight, everyone must take sides during a group get-together.

Sheldon and Bernadette hang out together while the rest of the gang go to a wine bar, where they run into Penny’s old boyfriend, Zack.

Penny struggles to bond with Leonard's mother when she comes for a visit. Meanwhile, Sheldon hires Stuart to spend the day with Amy.

Chaos ensues in the season nine finale when Leonard's recently divorced parents and Sheldon's devoutly religious mother come to town.