After discovering the wonders of Tinder, a curious couple goes looking for a threesome and gets a proposition from a friend.

Change doesn’t come easy for the gang when J.D. considers moving closer to his son. Meanwhile, Turk gets comfortable as chief of surgery, while Ted and Gooch reach a new…

J.D. manages to still bother Dr. Cox despite being away on a vacation from the hospital. Meanwhile, Turk and Carla have some big news to announce.

It’s Ted’s lucky day when he falls head over heels in love with an ukulele player, and Dr. Cox realizes he cannot handle everything that is thrown at him.

Sheldon beta-tests an MIT invention after hearing it can help him read people’s emotions. Also, Leonard can’t hide his feelings when Penny announces her brother is coming to town, and…

When a mistake comes to light, Sheldon makes Leonard walk a mile in his shoes; Penny decides to confront Raj’s ex.

When a mistake comes to light, Sheldon makes Leonard walk a mile in his shoes; Penny decides to confront Raj’s ex.

When Leonard receives an exciting opportunity to work overseas, Penny and Sheldon are thrown for a loop.

Amy and Sheldon’s relationship takes a surprising turn during a game of “Dungeons & Dragons”; Lucy and Koothrappali have an awkward date.

Amy tries to help Sheldon get over his compulsive need for closure when one of his favorite TV shows is canceled; Raj discovers a secret about Lucy.

Leonard, Sheldon and Wolowitz talk to junior high girls about science-related careers; Raj plans a date with Lucy.

After a bad date, Koothrappali decides to never leave his apartment; Penny’s acting skills impress Sheldon.

The guys search for a perfect Valentine’s Day gift for their significant others; Stuart and Raj host a “lonely people” party at the comic book store.

Marshall and Lily drag the gang to Atlantic City to elope, and their quest to overcome the three-day wait for a marriage license crosses them with some Chinese gamblers, a…