"The Comet Polarization"

On The Big Bang Theory Season 11 Episode 21, friendships end up being threatened when Koothrappali takes credit for Penny's astronomical discovery.

"The Reclusive Potential"

On The Big Bang Theory Season 11 Episode 20, Penny and Bernadette improvise after Amy doesn't like the tame bachelorette party they planned for her.

"The Tenant Disassociation"

On The Big Bang Theory Season 11 Episode 19, when Leonard learns Sheldon is the president of the tenants association, he decides to run against him.

"The Gates Excitation"

On The Big Bang Theory Season 11 Episode 18, Sheldon thinks he is the victim of an April Fools prank, and Penny gets the opportunity to host Bill Gates at work.

"The Athenaeum Allocation"

On The Big Bang Theory Season 11 Episode 17, Bernadette and Wolowitz must decide who should stay at home with the kids, while Leonard looks for a wedding venue.

"The Neonatal Nomenclature"

On The Big Bang Theory Season 11 Episode 16, when Bernadette won't go into labor, all her friends try different tactics to get things started.

"The Novelization Correlation"

On The Big Bang Theory Season 11 Episode 15, Sheldon petitions Wil Wheaton to appear on the new Professor Proton show, but Wil offers a role to Amy instead.

"The Separation Triangulation"

On The Big Bang Theory Season 11 Episode 14, when Sheldon rents his old room back for a quiet place to work, he drives Leonard crazy when he is a model tenant.

"The Solo Oscillation"

On The Big Bang Theory Season 11 Episode 13, Amy and Leonard bond during a series of science experiments after Sheldon kicks Amy out so he can work solo.

"The Matrimonial Metric"

On The Big Bang Theory Season 11 Episode 12, Sheldon and Amy devise secret experiments to discover who is most qualified to be best man and maid of honor.

TBBT Quotes

Leonard: Hi. I'm Leonard. You are beautiful. You pop, sparkle and buzz electric. I'm going to pick you up at eight, show you a night you will never forget.
Raj: Where are we going?

It's very simple. Scissors cuts paper, paper covers rock, rock crushes lizard, lizard poisons Spock, Spock smashes scissors, scissors decapitates lizard, lizard eats paper, paper disproves Spock, Spock vaporizes rock, and, as it always has, rock crushes scissors

Sheldon