The Best Episodes Written By Stephen Engel

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

Sheldon and the gang are confused when a young grad student is attracted to him.

With his friends knowing how sour he acts when sick—and avoiding him as a result—Sheldon is nursed by Penny, who hasn't a clue what she's in for.

When they're invited to present at a physics conference, Sheldon's reluctance to share the credit leads to a tiff between him and Leonard, and Penny's intervention only exacerbates the situation.

Raj gets an inflated ego and makes a play for Penny after being referenced in a magazine article.

Sheldon finds himself booted from the gang's Physics Bowl team and replaced with Leslie, so he forms his own team, hoping to prove he's superior.

Leonard, Sheldon and Wolowitz are ecstatic to learn that a famous science-fiction actress (Summer Glau) is on board the train they are taking to San Francisco.

Sheldon is thrilled when Leonard starts dating a woman who meets Sheldon's stringent standards.

When delivery of another collectible leads to Penny's lashing out at Leonard, he decides it's time to give up his habit, much to his friends' protestation.

With Sheldon rattled over meeting Dennis, a 15-year-old physicist who's smarter than he, Leonard helps him look for a way to debunk Dennis's research.

Dave puts the kids on a strict allowance, since they're always asking him for money. Vicky supports him on this... that is, until she, too, is put on a budget and is unable to buy the Prada boots she's always wanted. Meanwhile, after spending all his allowance money on the first day at Medieval Times, Larry asks Mike to loan him some money. And, in order to earn some extra money, Hillary starts an escort service for the nerdy boys at school.

Dave isn't happy when Taye's family is invited over for a barbecue by Vicky, and has a hard time getting along with Taye's father, Omar. At the barbecue, Omar mistakes some of Dave's comments as racist, because he's a wealthy, African-American. However, when Vicky insists that he go apologize to him, Dave finds himself having a great time at Omar's country club. When he gets home, though, he finds out that Hillary and Taye are on the verge of breaking up.

When Dave thinks the kids are getting away with too much, he implements a zero-tolerance, pro-spanking policy, since talking to them just isn't working. However, they all think he's bluffing and don't take him seriously. After Larry becomes the first to be spanked, he moves in with his friend, Kenny. Now, Child Protective Services is called and Dave will have to answer to them.

Thinking that Hillary will be grateful, Dave takes the blame when she gets pulled over for reckless driving while she's taking driving lessons. However, Hillary isn't grateful at all when this leads Dave to be arrested for DUI and goes to court to try and settle things. Vicky, meanwhile, forgets to register Larry for Shakespeare camp, while Dave and Mike take up online poker.

When Larry decides to run for president, Dave is supportive of his son's interest in leadership, until he learns that Larry is actually running for president of the Chess Club. Dave makes a strategic move to prevent Larry from becoming the biggest geek in school. Meanwhile, Hillary thinks she's going to become the next pop star, and after finding an empty condom wrapper in Mike's pants, Dave and Vicki face the dreaded sex talk.

After a car accident, Dave and Vicky decide to look over their living wills again, and ask their friends Jeff and Mindy to become their children's legal guardians should anything happen to them. They can't accept due to already doing the same thing for their other friends, so disagreements between Dave and Vicky start up, causing a huge fight. Larry thinks they may be getting a divorce, so he, Mike, and Hillary come up with a plan to get them back together.