Caroline tries to build herself a Murphy bed, the kind which folds into the wall, in Max's apartment. Meanwhile, the chemistry between Max and Johnny heats up.

Jim advises a player on the Celtics to take one of his recent losses less personally, sparking a controversy that forces the Kearney clan to confront their spiritual beliefs.

Alan goes too far in effort to collect $38 he loaned to Charlie. Meanwhile, Evelyn arranges a job for Jake.

Alan, Jake and Charlie all decide to try new things. Alan is dating more than one woman, Charlie learns to cook and Jake experiments with beer.

Walden's attracted to a mom at the kids' gym.

Walden and Alan try to convince Louis that Santa's real.

Herb asks Alan if he can go on a date with Lyndsey.

The Hecks call a meeting to deal with their bickering.

A stubborn Mike goes to the dentist.

Leonard and Sheldon's friendship is tested; Wolowitz's relationship with his mom causes a threat to his masculinity.

When the entire gang competes in a scavenger hunt designed by Raj, it brings out the best - and worst - in everyone.

Beverly Hofstadter writes a psychology book about Leonard which Penny buys and reads. Sheldon wants to ruin something for Amy after she ruins an Indiana Jones movie for him and Raj and Stuart try online dating.

Ursula dumps Joey but doesn't plan to tell him, so Phoebe disguises herself as her twin to break the news. Rachel cajoles Monica into trading identities so she can use Monica's health insurance for a sprained ankle.

Rachel interviews for a job as an assistant buyer at Saks Fifth Avenue. She also sees another side of the usually docile Ross when the girls face the boys during a not-so-friendly game of poker.

The gang searches frantically for Marcel, who slipped out of the apartment while Rachel was baby-sitting him. Rachel, who doesn't know that Marcel is an illegal pet, ends up calling Animal Safety.

Rachel and Barry start dating again which is slightly awkward because he's now engaged to Mindy. Chandler goes nuts when a woman he likes won't return his calls. The friends discover someone is spying on them.

Walden's attracted to a mom at the kids' gym.

Walden and Alan try to convince Louis that Santa's real.

Herb asks Alan if he can go on a date with Lyndsey.

Frankie's told her days of having kids are over.

The Hecks call a meeting to deal with their bickering.

A stubborn Mike goes to the dentist.

Leonard and Sheldon's friendship is tested; Wolowitz's relationship with his mom causes a threat to his masculinity.

When the entire gang competes in a scavenger hunt designed by Raj, it brings out the best - and worst - in everyone.

Beverly Hofstadter writes a psychology book about Leonard which Penny buys and reads. Sheldon wants to ruin something for Amy after she ruins an Indiana Jones movie for him and Raj and Stuart try online dating.

Ursula dumps Joey but doesn't plan to tell him, so Phoebe disguises herself as her twin to break the news. Rachel cajoles Monica into trading identities so she can use Monica's health insurance for a sprained ankle.

Rachel interviews for a job as an assistant buyer at Saks Fifth Avenue. She also sees another side of the usually docile Ross when the girls face the boys during a not-so-friendly game of poker.

The gang searches frantically for Marcel, who slipped out of the apartment while Rachel was baby-sitting him. Rachel, who doesn't know that Marcel is an illegal pet, ends up calling Animal Safety.

Rachel and Barry start dating again which is slightly awkward because he's now engaged to Mindy. Chandler goes nuts when a woman he likes won't return his calls. The friends discover someone is spying on them.

Walden risks losing Louis when his secret with Alan gets out.

Walden joins a group for adoptive fathers - without Alan.

Alan breaks up with the social worker to be with Lyndsey.

Lexie confesses to Sue that she has a crush on Axl.

Axl runs into just about all of his ex-girlfriends at a part.

Brick spends a weekend with Axl at college to par-tay!

Amy starts working at Caltech which causes friction with Sheldon. Howard agrees with Sheldon who mentions this to Bernadette causing a big fight for the Wolowitzes.

Sheldon's latest scientific breakthrough leaves him feeling like a fraud and a romantic gesture between Howard and Bernadette causes Penny to up her game with Leonard.

When Professor Proton asks Leonard for help with an experiment, Sheldon retaliates by befriending Proton's rival, Bill Nye.

When Monica's credit card is stolen she ends up making friends with the thief. Ross discovers Marcel has reached sexual maturity and needs to be with his own kind, so he tries to get him into the "Harvard" of all zoos.

After losing his virginity to her, Monica's boyfriend reveals he's a high school senior. Rachel has erotic dreams about Joey & Chandler. Whilst temping, Phoebe discovers no one at Chandler's office likes him anymore.

Carol goes into labour and Ross and Susan can't stop bickering over who gets to help more. Rachel flirts with an OB/GYN who has a love-hate relationship with women's private parts and Joey ends up assisting a birth.

During Rachel's birthday party, and while Ross is in China, Chandler lets it slip that Ross is in love with her. Joey's girlfriend wants to sleep with him but his participation in a fertility study is preventing this.

In desperate need of a new apartment, Abby turns to Gurgs and her unconventional real estate skills.

Gurgs's tween nephew and some of his fellow students visit the court for a school project.

Alan is sure that things will turn bad when Charlie starts dating his receptionist.

Upon discovering Miss Pasternak, Jake's former 5th-grade teacher, turned to stripping after their fling, Charlie tries to help her turn her life around.

Caroline drags Max to a cake-decorating class to increase their skill level and learn how to make more attractive cupcakes for their business.

Lexie confesses to Sue that she has a crush on Axl.

Axl runs into just about all of his ex-girlfriends at a part.