Phil and Claire decide to revisit last Valentine's Day's scenario; Jay plans an elaborate surprise for Gloria; an admirer comes between Cameron and Mitchell.

Mitchell causes drama over the guest list for Lily's birthday party; Jay and Gloria attempt to deal with the gathering of misfits.

Sheldon and Georgie attempt to find platinum by mining roadside gravel; Mary worries about Missy when she tries to overcome a batting slump with religion.

Meemaw is introduced to Dale's ex-wife; Sheldon is put in group with hesitant college students and forced to do a project with them.

Sheldon visits the CalTech campus; Georgie is angry at Mary for eavesdropping in on a conversation with his girlfriend; Meemaw tries to make Missy feel better.

Dr. Sturgis is greatly hurt when Sheldon says he plagiarized something; Mary attempts to find a girl-appropriate trophy to present at Missy's baseball ceremony.

The Cooper family cares for the school's librarian after George Sr. mistakenly forces her to go to hospital; Meemaw teaches Georgie about relationships.

Sheldon becomes determined to find the perfect next-door neighbors; Missy feels conflicted when she pitches against her own boyfriend.

Chandler and Ross fight over ownership of a joke published in Playboy; a broke Joey starts working at Central Perk; Phoebe's wayward remark causes trouble.

After her father cuts her off, Rachel's sister, Jill, comes to town and goes on a date with Ross; Joey gets in trouble for giving female customers free food.

Chandler admits that he hasn't cried since he was a child; Phoebe discovers that Ursula is starring in porno movies using her name.

Barry and Mindy's impending divorce prompts the gang to fantasize about what their lives might be like if they'd all taken different courses.

The conclusion of the "what if" episode shows Ross having a threesome with Susan and Carol, Rachel kissing Joey and Monica and Chandler hooking up regardless.

Joey enters himself into a medical study in order to afford some new headshots; Rachel and Phoebe take lessons from Ross in Unagi.

Ross ponders dating a student who is smitten with him, even though it could cost him his job; Rachel moves in with Joey after her apartment burns down.

Joey's fridge is broken and he tries to cajole his friends into helping him buy a new one; Phoebe, Monica and Chandler compete to get Rachel a date for a ball.

Joey gets an audition for the lead character in a new TV show but misses the audition because Chandler forgot to relay the message of the time change.

Ross asks his friends to keep him company when he meets Elizabeth's dad for the first time; Joey may get fired when he fights with C.H.E.E.S.E's operator.

Paul threatens to get Ross fired if he doesn't stop seeing Elizabeth; Joey wants to get his picture on his dry cleaner's wall of fame.

Chandler and Phoebe go out shopping together to find a ring for Monica; Rachel wants Paul to open up, but he opens up a bit too much.

Leonard and Sheldon have a big, drawn-out quarrel that drives Leonard to move out; Raj decides to take care of Mrs. Wolowitz while Howard is gone.

The guys try to give their girlfriends the perfect Valentine's Day; Raj and Stuart decide that they are going to throw a "lonely people" party.

Raj falls into depression after a girl he meets at the comic book store walks out on him during a coffee date; Penny impresses Sheldon with her acting.

Leonard, Sheldon and Howard return to junior high school to talk to the girls about careers in science; Raj plans a big date with Lucy.

Howard has an internal struggle about opening a letter from his father; Leonard and Penny decide to throw a "grown-up" cocktail party at the apartment.

Leonard, Sheldon and Raj get in an all-out fight for the tenure position at the university, and the competition gets so fierce that the girls get involved.

Sheldon begins to feel lost after one of his favorite television shows gets canceled too soon; Raj discovers an interesting secret about Lucy.

Dwight takes it upon himself to help with overall office efficiency by installing a doomsday device that will get them all fired if they find too many slip-ups.

When Pam takes maternity leave, she has Dwight try to prove that Jim finds her temp attractive; Robert California asks to join Andy, Darryl and Kevin's band.

Attempting to motivate and inspire everyone in the office, Andy decides to take them on a field trip to Gettysburg; those who stay behind brainstorm for ideas.