During a game, Sheldon revisits Christmas memories. Amy, Penny and Bernadette look for a date for Koothrappali.

Leonard and Sheldon hire the host (Bob Newhart) of their favorite childhood TV show to perform. meanwhile, Bernadette and Howard run into trouble while dog-sitting for Raj's pet.

While Sheldon is in Texas, the rest of the gang realizes how much he has changed their lives as they decorate the apartment Christmas tree.

After the guys can’t get Comic-Con tickets, Sheldon tries to hold his own convention and winds up spending a wild night with James Earl Jones.

Penny's flirtatious sales techniques work a little too well.

Amy forces Sheldon to celebrate a Victorian Christmas.

Everyone awaits the reopening of Stuart's comic bookstore.

Sheldon and Amy try hanging out as friends when they spend Thanksgiving together at the aquarium. Also, Wolowitz reluctantly agrees to volunteer at the soup kitchen with Bernadette, Raj and Emily.

Sheldon struggles to contain his jealousy when CalTech geologist Bert wins the MacArthur Genius Fellowship. Stephen Hawking returns for a guest appearance.

A battle ensues when Leonard and Sheldon argue over who will get custody of their shared belongings. Christopher Lloyd guest stars.

Sheldon and Amy visit Leonard and Penny for the first time since the holidays and share details about their terrible trip to Texas. Laurie Metcalf returns as Sheldon's mother.

Amy answers Sheldon's proposal.

Amy's parents and Sheldon's family arrive for the wedding.

The guys try to crash Wil Wheaton's celebrity D&D game.

In the series finale, the gang travels together into an uncharted future.

Penny starts dating Leonard's handsome colleague; Leonard and his friends are tortured by Sheldon's obsession with gift-giving etiquette.

Leonard and Koothrappali escort a heartbroken Wolowitz to Las Vegas. Sheldon becomes locked out of his apartment so must stay with Penny.

A Christmas visit from his mother has Leonard discovering she's kept a lot of news from him that she shares with Sheldon and worrying if she'll approve of his romance with Penny.

Sheldon winds up in traffic court when he gets a ticket because of Penny.

An embarrassing secret of Wolowitz's comes to light, while Sheldon and Raj have a small war at work.

Sheldon's answers during an FBI interview put Wolowitz's security clearance in jeopardy.

Sheldon and Leonard get invited to a party at Wil Wheaton's house, and Howard gets an out-of-this-world opportunity.

When Wolowitz gets to work with Stephen Hawking, Sheldon is willing to do anything to meet his hero.

During a game, Sheldon revisits Christmas memories. Amy, Penny and Bernadette look for a date for Koothrappali.

Leonard and Sheldon hire the host (Bob Newhart) of their favorite childhood TV show to perform. meanwhile, Bernadette and Howard run into trouble while dog-sitting for Raj's pet.

While Sheldon is in Texas, the rest of the gang realizes how much he has changed their lives as they decorate the apartment Christmas tree.

After the guys can’t get Comic-Con tickets, Sheldon tries to hold his own convention and winds up spending a wild night with James Earl Jones.

Penny's flirtatious sales techniques work a little too well.

Amy forces Sheldon to celebrate a Victorian Christmas.

Everyone awaits the reopening of Stuart's comic bookstore.

Sheldon and Amy try hanging out as friends when they spend Thanksgiving together at the aquarium. Also, Wolowitz reluctantly agrees to volunteer at the soup kitchen with Bernadette, Raj and Emily.

Sheldon struggles to contain his jealousy when CalTech geologist Bert wins the MacArthur Genius Fellowship. Stephen Hawking returns for a guest appearance.

A battle ensues when Leonard and Sheldon argue over who will get custody of their shared belongings. Christopher Lloyd guest stars.

Sheldon and Amy visit Leonard and Penny for the first time since the holidays and share details about their terrible trip to Texas. Laurie Metcalf returns as Sheldon's mother.

Amy answers Sheldon's proposal.

Amy's parents and Sheldon's family arrive for the wedding.

The guys try to crash Wil Wheaton's celebrity D&D game.

In the series finale, the gang travels together into an uncharted future.

Penny starts dating Leonard's handsome colleague; Leonard and his friends are tortured by Sheldon's obsession with gift-giving etiquette.

Leonard and Koothrappali escort a heartbroken Wolowitz to Las Vegas. Sheldon becomes locked out of his apartment so must stay with Penny.

A Christmas visit from his mother has Leonard discovering she's kept a lot of news from him that she shares with Sheldon and worrying if she'll approve of his romance with Penny.

Sheldon winds up in traffic court when he gets a ticket because of Penny.

An embarrassing secret of Wolowitz's comes to light, while Sheldon and Raj have a small war at work.

Sheldon's answers during an FBI interview put Wolowitz's security clearance in jeopardy.

Sheldon becomes concerned when everybody begins to hang out at Raj's apartment and discovers Leonard is the center of the group.

Sheldon and Leonard get invited to a party at Wil Wheaton's house, and Howard gets an out-of-this-world opportunity.

When Wolowitz gets to work with Stephen Hawking, Sheldon is willing to do anything to meet his hero.

During a game, Sheldon revisits Christmas memories. Amy, Penny and Bernadette look for a date for Koothrappali.

Leonard and Sheldon hire the host (Bob Newhart) of their favorite childhood TV show to perform. meanwhile, Bernadette and Howard run into trouble while dog-sitting for Raj's pet.

While Sheldon is in Texas, the rest of the gang realizes how much he has changed their lives as they decorate the apartment Christmas tree.

After the guys can’t get Comic-Con tickets, Sheldon tries to hold his own convention and winds up spending a wild night with James Earl Jones.

Penny's flirtatious sales techniques work a little too well.