Some Season 2-era fun for everyone.

Castle:

"I'm telling you, there's no apostrophe."

"It's the possessive form, Chuck. Of course there's an apostrophe. And stop reading over my shoulder. It's… distracting me."

"Because I'm so dreamy?" The patented eyebrow dance made an appearance. Sarah took a deep breath.

"That's not relevant."

"Look, I know what I'm talking about with this one. I got into a whole internet argument with a guy on a World of Warcraft forum about it."

"That doesn't really shore up your 'dreamy' self-assessment, Chuck."

"When it's a contraction, you use the apostrophe. But the possessive form of "its" is just eye, tee, ess. As in, 'Sarah Walker's hubris is its own worst enemy.'"

"Well, you're wrong. Don't feel bad, Chuck; it's okay to be wrong sometimes."

Chuck leaned in close to Sarah and quirked an eyebrow.

"Care to make it interesting, Agent Walker?"

Chuck vs the Friendly Wager

It had been a strange week for Sarah Walker.

While the lack of international evildoer activity had given the team an opportunity to catch up on paperwork and organizational maintenance, the boredom associated with the downtime had been affecting all of them differently. Casey had taken to busy work – inventory, maintenance, and the almost frighteningly precise cleaning of his multitude of firearms. Chuck had become almost unbearably nosy, following Sarah around Castle like a playful pet she'd adopted from the nerd pound and trotting out a seemingly endless parade of questions. And Sarah—

Sarah had been… a certain kind of restless.

She'd experienced downtime before, but it had been during her partnership with Bryce, where she had been used to a certain level of physical intimacy. But now, nearly two years since the last time she'd had… well, that kind of intimacy, Sarah was noticing that she was having something of a hard time controlling her urges.

Like right now, with Chuck doing a celebratory dance in the depths of Castle after having shown her five different online sources corroborating his grammar lesson, Sarah was finding it extremely difficult to keep from grabbing his face and kissing the stupid off of it. Just all of the stupid right off his stupid face.

"I can't believe being right about an apostrophe is bringing you this much happiness."

Chuck dialed down his gyrations just enough to keep Sarah in his field of vision. "It's not the win, Sarah, it's the prize. The prize!" Chuck dialed back up to maximum gyration to punctuate.

"Have you been working out?"

"What's that again?"

Sarah shook her head. "Nothing, forget it. I can't believe you're this happy about karaoke."

"But, Sarah- the prize isn't the simple act of going to karaoke. It's the fact that I get to choose the song you perform at said karaoke. And by the way, I can't believe you could only come up with me giving you a back rub back at your hotel room for your side of the bet. Lame."

Sarah narrowed her eyes at Chuck. "Yes," she deadpanned. "That would have been so very lame. For you. Good thing you won."

"Oh, man," Chuck laughed, rubbing his hands together. "Wait 'till Ellie hears."

XXX

Casa Bartowski:

"You WHAT?"

Chuck had disappeared into his bedroom to change out of his work clothes, leaving Sarah alone with a suddenly very agitated Ellie Bartowski. She took a half step back as Ellie grabbed both her shoulders, face screwed up into a panicked grimace. "I, uh… lost a bet with Chuck? Ellie, you're… a lot stronger than you look. Also, you smell like cinnamon."

"It wasn't a karaoke bet, was it? Sarah, please tell me you didn't do a karaoke bet with Chuck. You're so young and pretty. Bad things shouldn't happen to pretty people."

"Like, really strong. Have you been working out? You look good."

"Sarah!" Ellie shook her a bit, snapping her back to the moment. "Was. It. A. Karaoke. Bet?"

"Well, yes, but—"

"Oh, god," Ellie moaned, covering her mouth with her hands. Sarah knew Ellie was trying to tell her something important, but the unintentionally sexy noise she'd just made was playing havoc with her concentration.

"I like that top you're wearing. We should hang out more."

"Thanks," Ellie replied distractedly, starting to pace back and forth. "Nordstrom's. Sarah, I don't think you understand the gravity of the situation, here. Chuck… he's… diabolical when it comes to picking songs for other people to sing." Ellie finally stopped pacing and sat down on the couch. Sarah sat next to her, a little closer than usual.

"I'm sure you've figured out by now that Chuck has a real talent for noticing things about people. He pays attention to the tiny details when he's interacting with someone, and files all that information away, like he's got this little database in his brain. And under normal circumstances, it's really sweet. He uses those powers for good. He'll remember important days, or someone's favorite band or food, and use that to be there for people when they need a pick-me-up."

"Totally," Sarah said, nodding and staring at Ellie's lips. "He's sexy."

"But the karaoke bet… something happens to Chuck, Sarah. When he wins one of those bets, he uses every little scrap of information to choose the absolute worst song possible for you to sing. He's so good at it."

"Sounds really intense. But soft. Like a back rub."

"He had Devon perform 'Feel Like a Woman' by Shania Twain. For Morgan it was 'Bohemian Rhapsody.' I thought he was going to pass out. His lungs are so tiny!"

"Where is Morgan, anyway?" Sarah asked, looking around the apartment. "I like his beard."

"But for me it was the worst," Ellie continued, staring off in front of her but clearly not seeing anything. "For me… it was 'Big Bottom' by Spinal Tap." Ellie shuddered, then sprung up off the couch.

"Devon!" She called out, marching towards the bedroom. "We're going to watch Sarah sing karaoke tonight!"

Sarah followed Ellie with her eyes, then sighed deeply and sunk back into the couch. "Hate to see her leave, but I love to watch her go."

Chuck finally emerged from his bedroom, dressed in a casual button down and jeans. "You ready?"

"Yup," Sarah said, staring in the direction Ellie had just gone. "Wait, what?"

Chuck gestured vaguely in the direction of the front door. "The… karaoke…?"

"Right," Sarah said, standing up. "I knew that. Um… it looks like Ellie and Devon are going to be joining us."

"The more the merrier," Chuck said, smirking. Sarah narrowed her eyes at him.

"I don't like the way you said that."

XXX

Café Brass Monkey:

Sarah pinched the bridge of her nose. "I don't know what made me think Jeff and Lester wouldn't somehow be involved in this."

Across the bar, Jeff and Lester were manning the sound equipment, apparently having an argument over their individual artistic visions. Well, as much of an argument that's possible when one participant is barely conscious. Lester's impassioned gestures were doing an impressive job of picking up the slack, however.

"And Morgan," Chuck said, giddily pointing to his little friend as he set up a video camera. "Morgan's here, too. And he brought Anna!"

"Do you ever think about growing a beard?"

"I dunno," Chuck said, searching the crowd. "They seem really scratchy."

"Yeah, they scratch all kinds of itches."

"Oh, wow, Casey made it!" Chuck pointed to the bar, where Casey was hunched over what one could only assume was some very powerful bourbon. Upon spotting Chuck and Sarah, he gave a wolfish grin.

"Does Casey look like he's been working out more?"

"I'm going to go get you all set up with Jeffster on your song," Chuck said excitedly. "You okay on your own for a little bit?"

"Sure," Sarah shrugged. "I'll grab a drink and go talk to Anna."

XXX

"Not much, I just have one of those metabolisms where I don't really need to exercise. Why do you ask?"

"No reason," Sarah shrugged. "You look good. I like that lipstick. We should hang out more."

Anna quirked an eyebrow at Sarah as Chuck joined them. "You ready?" he asked, rubbing his hands together.

Sarah just nodded, still looking at Anna. "Yup," she replied, taking a sip of her Mojito. "Wait, what?"

"For your song. You're up next."

"Right, yeah. That's what I meant. Let's do it. I mean, I'm gonna do it. I should stop saying 'do it.' I can do it. I mean do that. I am a goddamned train wreck right now." Sarah spun on her heel and strode towards the stage. Chuck smiled devilishly as he turned to Anna.

"She's really nervous about singing, huh?"

Anna shook her head as Chuck turned his attention back to Sarah, who had paused at the bar and was now dipping her fingers in a glass of water and flicking the droplets at her face. "You are the most clueless person in the world."

"I'm gonna get a good seat. I don't want to miss anything."

"To late for that," Anna muttered, taking a gulp of her Mai Tai.

XXX

Sarah stood by the stage, waiting her turn while basically every person she knew in Los Angeles settled into seats to watch. Sensing eyes on her, she looked over at Lester as he leered.

"Sarah," he said in that creepily over-seductive tone. "So glad to see we both heed the siren song of… well… song."

"I lost a bet, Lester," Sarah replied flatly.

Lester examined her for a moment before responding. "I don't think that's entirely the case." he said, thoughtfully. "I think you're looking for ways to expend some extra energy. You see, I'm extremely sensitive to the female aura. Yours is quite the shade of lavender at the moment. Am I correct in assuming you're… craving the touch of your fellow man?"

Sarah stared incredulously at Lester. "Not all of them, no."

"It's time," Jeff called in his dazed monotone. Lester huffed and moved towards the microphone.

"I'll introduce you," he snapped over his shoulder. "Try not to sully my passion with your lack of talent."

"You've sullied enough passion for the both of us," Sarah muttered under her breath as Lester took the stage. She shook her head at her current situation. "I have literally topped governments," she mused.

"Ladies and Gentlemen, Jeffster is proud to sponsor Amateur Night here at the Brass Monkey, allowing the showcase of those far less talented than we." If Lester had heard the scattering of boos from the crowd, he gave no indication. "The real show will start in about five minutes, but for now please put your hands together for Sarah… something or other."

The crowd clapped enthusiastically as Sarah took the stage. Lester lingered by the microphone as long as possible, soaking in applause that wasn't quite meant for him. Finally he relinquished the mic to Sarah, who tried not to think about how close it had been to Lester's mouth as she took it.

Sarah furrowed her brow as the song started. It was very familiar. A deep synthesizer melody, definitely from the eighties. Her eyes scanned the people in the crowd, who were all suddenly cheering wildly as they recognized the song. Morgan was waving at her, trying to catch her attention, and when she met his eyes he gestured frantically at a screen in front of her with lyrics on it.

Suddenly Sarah's brain clicked on the name of the song. She glared at Chuck, who was sitting smugly in the front row, a calm and confident contrast to the rest of the frantic crowd. She didn't have much time to glare, though; the screen showed that it was time to start singing.

"I made it through the wilderness," Sarah timidly sang into the microphone, in a voice that had to be embarrassingly off-key. The crowd, however, seemed to really be enjoying her awkwardness, Chuck especially. "Somehow I made it through…"

Yeah, Chuck was really loving this. Arms crossed confidently against his chest, body tilted back in his chair, a big shit-eating grin on his face. Ellie was right; he'd picked a perfect song to embarrass Sarah.

Well, if he was going to have fun, she figured she may as well, too. She looked him right in the eye and sang the next lines with a little more confidence.

"Didn't know how lost I was

Until I found you…"

Sarah pointed directly at Chuck on the last word. The crowd cheered he newfound enthusiasm, as Chuck's grin lost a tiny bit of brilliance. Okay, she thought. Let's see if we can turn this around. Sarah took a single step off the stage to sing the next line, and Chuck's eyes grew wide.

"I was beat

Incomplete…"

Another step towards Chuck. His eyes darted around nervously. And was that a bead of sweat on his forehead?

"I'd been had, I was sad and blue…"

Sarah was within reach of Chuck now, and his eyebrows shot up to his hairline. She reached out to drag a finger down his arm to punctuate the next lines.

"But you made me feel

Yeah, you made me feel

Shiny and new…"

Sarah took mercy on Chuck and skipped back up to the stage, spinning around to face him again for the title of the song.

"Like a virgin…"

Shrill whistles broke out from the crowd as Sarah pressed her fingers over her heart, trailing them down to her midsection.

"Touched for the very first time

Like a virgin

When your heart beats

Next to mine"

If Sarah squinted, she supposed she'd be able to see smoke coming out of Chuck's ears. She started her slow approach towards him again, and panic rose in his eyes.

"Gonna give you all my love, boy

My fear is fading fast

Been saving it all for you

'Cause only love can last"

Sarah dropped herself into Chuck's lap for the next verse, and cheers erupted from the crowd again.

"You're so fine

And you're mine

Make me strong, yeah you make me bold

Oh, your love thawed out

Yeah, your love thawed out

What was scared and cold"

She popped out of his lap and jumped back up on stage again, strutting slowly back and forth.

"Like a virgin, hey

Touched for the very first time

Like a virgin

When your heart beats

Next to mine"

Sarah placed the mic back into the stand to sing the next verse, grabbing hold of the mic stand and rocking it back and forth as she leaned forward and back.

"You're so fine

And you're mine

I'll be yours

'Till the end of time

'Cause you made me feel

Yeah, you made me feel

I've nothing to hide"

She pulled the mic out of the stand and mad her way over to the bar, leaping up onto the bar top in one easy stride. The crowd went nuts, and the bartender gaped.

Like a virgin, hey

Touched for the very first time

Like a virgin

When your heart beats

Next to mine

Sarah dropped down again to the stage, and stalked her way back over to Chuck, a hungry look in her eyes.

"Like a virgin, ooh ooh

Like a virgin

Feels so good inside

When you hold me

And your heart beats and you love me

Oh ohh…"

Done singing, Sarah dropped herself back into Chuck's lap. As the song ended, the crowd's cheers grew almost deafening. Sarah leaned in and spoke into Chuck's ear, her lips ghosting across his skin.

"Congratulations on winning the bet."

"Um… thanks?"

"Wanna get out of here?"

"I do. I really do."

Sarah smiled triumphantly, stood up, and waited for Chuck to join her. Chuck, however, remained seated.

"Chuck?"

"Yeah, I'm gonna need a minute."

"Oh. Okay. I've got to talk to Casey before we go anyway."

Chuck gave a nervous wave as Sarah walked to the bar where Casey was sitting.

"Walker."

"Casey."

"Nice job on the song."

"Thanks."

"You been working out?"

"I have, thanks for noticing. Listen, I'd really appreciate it if you could do something about the recording Morgan made of that whole thing. I'd owe you one."

"Consider it done," Casey nodded amicably if a bit nervously, holding his scotch up in a casual salute.

"Thanks." Sarah watched him for a moment, but he made no indication of movement. "Um…"

"I'm gonna need a minute."

"Oh." Sarah and Casey looked at each other awkwardly for a moment. "Can we never—"

"—Speak of this again? Top shelf, Walker."

Sarah gave a thumbs up, turned around to leave, and bumped into Chuck.

"Hey! Ready to go?"

"On so many different levels, yes."

Chuck led Sarah away, leaving Casey gripping his drink with white knuckles. "Hate to see her leave…"

Chuck and Sarah were almost at the door when Anna stepped in their way.

"That was amazing," Anna gushed to Sarah. "We should totally hang out more."

"I know, right? Your hair is so pretty!"

"Okay," Chuck said, pulling Sarah's hand out of Anna's hair, "thanks for coming, Anna, it's been fun, we've gotta go now, bye!"

As Chuck whisked Sarah towards the door again, Anna saw Sarah whisper something in his ear. She could just barely make out Chuck responding, "No, we are not asking her to join us."

Anna scowled at Chuck and Sarah's retreating forms.

"I shoulda hit that when I had the chance."

XXX

Sarah's Apartment:

"So, when you said 'back rub,' you meant…"

Sarah rolled over, pulled the sheets around her, and put her head on Chuck's chest. "You are the most clueless person in the world."

"So I've been told. Um… is this the part where we ponder the implications and gravity of what we've just done and how it impacts our lives and service to our country?"

Sarah breathed in deeply, lifted her head, and kissed Chuck passionately.

"No, this is the part where we do it again."

Chuck beamed a megawatt smile.

"We need to bet on stuff more often."

For the record, Horny!Sarah? Just about the most fun thing to write ever.