Warning: This recap contains storyline and character spoilers for "The Intimacy Acceleration" episode of The Big Bang Theory.
For the most reliably funny characters on The Big Bang Theory, you can't beat Sheldon and Howard. But when it comes to the most reliable comedy duo on the series, forget Sheldon and Leonard, or even Howard and the dearly departed Mrs. Wolowitz (RIP). Nope, the title belongs to Sheldon and Penny.
Remember the one where Penny procures for Sheldon the DNA of his hero, Leonard Nimoy (who had wiped his mouth on a napkin at the Cheesecake Factory where Penny worked)? And the one where Sheldon helps Penny launch her Penny Blossoms barrette business? Or when Sheldon had to help a naked Penny get dressed when she fell in her bathtub? And, a true gem, when Sheldon bans mooch Penny from the apartment, resulting in a game of one-upmanship that, ultimately, sees Penny one-up her alleged intellectual superior? All great episodes, and all because of the Sheldon/Penny adventures that are front and center.
Likewise in "The Intimacy Acceleration," in which the gang discusses a new experiment designed to test whether or not two people can be made to fall in love with each other in just a few hours. Sheldon wants to conduct his own version of the experiment by "imprison[ing] two street people." Wet blanket Amy cuts him off on that one. "Oh, so you can experiment on all the apes you want, but I want to manipulate the emotions of two captive human beings, and suddenly I'm the monster," he pouts, before he and Penny decide to test the theory themselves.
The two get a stack of cards with questions that are supposed to help them get to know each other. Who would they have dinner with if they could have dinner with anyone? Sheldon chooses himself, but he's impressed with Penny's answer of Robert Downey Jr., aka Iron Man. "Maybe after myself and I have dinner, we could meet you two for dessert," he suggests.
What power or ability would they each choose to have? Penny jokes she'd love to be able to get all Biblical on water by having the ability to turn it into wine, and Sheldon tells her she's using humor to avoid being vulnerable with honest answers. So she says she'd like to be as smart as him and the rest of their friends, and he admits he'd like her ability to read people, because he can't and it makes him insecure and stressed.
"Wow, I just felt this wave of affection for you," Penny says.
"You sure it's not just too much Bible juice?" he says, nodding to her glass of vino.
Penny: "And the wave is gone."
But the two do continue to bond, with Sheldon revealing a huge secret: Today is his birthday, something he hasn't even told Amy (he hates presents and people jumping out to yell "Surprise!"). They don't fall in love, of course, as they admit they see each other as siblings (except when Sheldon thinks of Penny as his mom sometimes).
And Penny once again one-ups her friend and neighbor: She lets the rest of the group know about the Birthday Boy, who's greeted with balloons and shouts of "Surprise!" when he walks into his apartment.
Elsewhere, Howard and Bernadette arrive back in Los Angeles after attending his mother's funeral, and they're missing something very important: the suitcase containing Mrs. W's ashes. It's found, but only after Howie 'fesses up to his wife that he's been feeling incredibly guilty about telling his mom he was too busy to drive her to the airport for her Sunshine State trip. Bernadette responds by telling the female airline rep she needs to find the MIA luggage ASAP, because "one way or another, we're walking out of this airport with a dead woman."
And in the C-story that serves no other purpose but to give the rest of the crew something to do in the episode, Leonard, Amy, Raj, and Emily (his girlfriend who's made such a small footprint in the storyline that we keep forgetting she exists) go to a zombie escape room night, and conclude they're all too smart for the game when they pay $200 for six minutes of fun.
Big Bang Bits:
* Leonard: "You can't create love in a few hours, right?"
Penny: "Careful… you're poking at the whole foundation of The Bachelor."
* Penny: "I'm not going to fall in love with Sheldon."
Amy: "That's what I said. Before I knew it, he pontificated his way right into my heart."
* Zombie escape room adventures? Real thing.
* Gary Con, the Wisconsin convention honoring the late Dungeons & Dragons co-creator Gary Gygax, the Con Sheldon wants Penny to promise to drive him to if he is able to make her fall in love with him? Real thing, too.
* Sheldon, responding to Penny agreeing to accompany him to Gary Con if they fall in love: "OK, babe, let's do this."
* Sheldon, refusing Penny's offer of wine: "You're not supposed to drink alcohol when operating heavy machinery."
Penny: "What heavy machinery?"
Sheldon points to his head.
* Sheldon, insisting to Penny that he's warm and soothing: "I'm like a human bowl of tomato soup."
* Sheldon on the failure of the experiment to make him fall in love with Penny: "Psychology has once again proved itself the doofus of the sciences."
* The Sheldon/Penny episodes referenced above: "The Bath Item Gift Hypothesis," "The Work Song Nanocluster," "The Adhesive Duck Deficiency," and "The Panty Piñata Polarization."
The Big Bang Theory airs Thursdays at 8 p.m. on CBS.