The Big Bang Theory – Season 8, Episode 23

G Leonard and Amy take an unexpected road trip to Arizona to pick up Sheldon, while Penny interviews for a job at Bernadette's company.

PGR When Sheldon is forced to teach a class, Howard surprises everyone by taking it!

G Howard's nervous when NASA asks him to throw out the first pitch at a baseball game. Meanwhile, Leonard and Penny try to prove Sheldon wrong after he claims that he and Amy are a superior couple.

G Raj's honesty about his past comes back to bite him after his girlfriend is cold to Penny. Meanwhile, the guys consider becoming part-owners in Stuart's comic-book store.

PGR With the girls away in Vegas for the weekend, the guys try to invent 'the next big thing,' but instead only come up with new ways to procrastinate.

G Sheldon and Raj see if they can survive intense heat - and each other - when they venture deep underground in the name of science.

G The boys try to help Penny out of an awkward work dilemma, when a smitten doctor shows up at her door after her flirtatious sales techniques work a little too well.

G When the gang recreates a high-school prom night on the roof of the guys' apartment building, Sheldon feels pressure to participate in all the typical romantic traditions.

G When Leonard gets minor surgery on his nose, Sheldon has a major overreaction. Meanwhile Howard and Bernadette work on their marriage in light of Raj's parents' impending divorce.

G As Sheldon records the final instalment of 'Fun with Flags', Bernadette is shocked to learn of her co-workers' true feelings from Penny.