1. When Sheldon returns from giving his speech in Fresno, he's wearing a black turtleneck.
Leonard has never seen Sheldon in a turtleneck before. In fact, he seems to remember Sheldon saying something once about how turtlenecks make him feel like he's choking.
"Are you going to a costume party as a beatnik?" Leonard asks, almost as soon as Sheldon walks through the door.
Sheldon looks at Leonard like he's lost his mind. "It's Saturday morning. Who would schedule such a party on a Saturday morning?"
Leonard sighs. Sometimes it drives him batty the way he has to spell out everything to Sheldon. "What's with the turtleneck?"
Sheldon looks down at himself, as if he's only just noticed he's wearing the turtleneck. "I'm into turtlenecks now," he finally says.
The scary part is how much Sheldon looks like Leonard Nimoy in his turtleneck. It's eerie. And Leonard wonders why Sheldon would want to wear a turtleneck in September. It's 80 degrees outside.
Sheldon wears turtlenecks for three days straight and then stops, never to don a turtleneck again.
"What happened to the turtlenecks?" Leonard asks one night after everyone has gone home after playing Rock Band.
Sheldon shrugs. "I'm over them," he says.
Weirder still, during this same period, Penny starts wearing a different scarf around her neck every day. "What's with the scarves?" Leonard asks her, one morning when they're both getting their mail. Things are still weird between them since they broke up last month and he's happy to have a conversational entrée.
She gives him an odd look. "I'm into scarves right now," she says. "Don't you ever read Vogue? They're very in."
A few days later, Penny seems to be over scarves.
2. Sheldon starts singing in the shower.
Leonard gets up and hears the shower running. It's 7:32 a.m. and Sheldon's right on schedule. But then he stops in his tracks. My God. Sheldon is singing.
Sheldon does not sing, unless he's drunk (and Sheldon's rarely drunk, especially at 7:30 a.m.). Leonard is relatively sure that the Roommate Agreement prohibits not only whistling but unnecessary non-videogame related singing. He'd go and look it up but he doesn't time this morning to pore over a hundred-page document with a magnifying glass.
And strangest yet, Sheldon seems to be singing the lyrics to "Tiny Dancer," although he's got them wrong.
"Hold me closer, Tony Danzaaaaa," Sheldon sings, belting it out over the spray of the shower.
First of all, since when has Sheldon become an Elton John fan? And, secondly, even if he is an Elton John fan, how is it possible that Sheldon would get the lyrics wrong? He has an eidetic memory.
Sheldon sings "Tiny Dancer" in the shower for more than a week and then he abruptly switches to a new song.
"Like a virgin, touched for the thirty-first time…."
3. Penny becomes abnormally nice.
Sure, Penny is a nice person. And she's always been nice to Leonard. But their breakup wasn't exactly pretty. They both said things to each other that they didn't really mean and it ended with Penny hurling a wineglass at Leonard's head and mutual slamming of the doors to their apartments.
Things were strained for more than a month after their breakup. Penny stopped casually dropping by to raid their refrigerator and watch free cable. She only came over for planned group events like Halo Night and only if Sheldon or Leonard had specifically invited her.
That's why it's odd that, all of a sudden, Penny seems to be over it. Totally over it. Suddenly she's hugging Leonard all the time, flashing him toothy smiles and calling him "sweetie" again.
Does she want to get back together? She must. She's at their apartment all the time, sprawled on the couch, drinking all their Diet Coke. One time, she even sits in Sheldon's place on the couch and Sheldon doesn't even make a peep. He must want Leonard and Penny to get back together, Leonard reflects. Sheldon had his initial objections to their relationship, but in the end, he seemed to appreciate its stability. Sheldon likes stability, predictability.
You still got it, Leonard thinks. You're the man.
4. Sheldon asks strange questions.
Sunday morning, and Leonard and Sheldon are sitting on the couch, watching an old Scooby-Doo cartoon. Tim Conway and Harvey Korman are the guest stars. The gang split up to explore a haunted house and Scooby and Shaggy get chased around by the ghost.
"Leonard," Sheldon says out of the blue. "Why do you suppose most men don't have multiple orgasms?"
Leonard nearly spits out his orange juice in shock. "What?"
"Why do you think most, if not all, men don't have multiple orgasms? I mean, many women are able to achieve multiple orgasms with relative ease, but it would seem that it's virtually impossible for men to do the same."
He stares at Sheldon through his glasses, but Sheldon's face doesn't give anything away.
"Women developed the ability as an evolutionary adaption so they could have sex with multiple mates and ensure the continuation of the species," Leonard says. Sometimes, although much too rarely, it's helpful to have an anthropologist for a father.
"I know that," says Sheldon, sighing. "It just seems patently unfair that most men need a sizable refractory period before being able to achieve another erection and, thus, an additional orgasm."
"What do you care? It's not like you have a girlfriend with multiple orgasms to be envious of. The only relationship you've ever had is with your right hand." It's mean, but it's the truth, Leonard thinks.
Sheldon gets up off the couch and stomps off to the fridge to grab a bottle of chocolate milk. "I just don't think it's fair, " Sheldon says. "Not fair at all."
5. Sheldon stops sleeping in his pajamas.
The building's fire alarm wakes Leonard at 3:14 a.m. He sits in bed, momentarily disoriented, wondering what all the ruckus is about. Then he realizes it's the alarm, hops out of bed, and finds his bathrobe and slippers in the dark. He rushes through the dark living room and out to the corridor outside the apartment.
He finds Sheldon already out in the hall, wearing only his white briefs. The alarm abruptly stops blaring. "It's probably a false alarm," Sheldon says grumpily, shivering. "I tried to inform the landlord that there appeared to be a short in the alarm system last week, but he hung up on me."
"Where are your pajamas?" Leonard says. Sheldon always wears pajamas. He once told Leonard that he'd never sleep without being fully covered because he worried that if there were a fire he'd end up on the street in his underwear or worse.
If you look up "modesty" in the dictionary, Sheldon's picture is right there beside the entry.
Sheldon says, "I didn't feel like wearing them tonight. I was hot."
It's an unusually cold October evening.
Penny's out in the hallway, too, wrapped in a thin cotton kimono. Leonard tries not to dwell on the fact that he can see her nipples through the fabric. "He was so fast, Leonard!" she says. "You should've seen him shoot through your front door. Just crazy fast."
The three of them start down the stairs. Off in the distance, Leonard hears a fire truck.
"I sometimes have superhuman powers in emergency situations," Sheldon says. "I'm practically a superhero."
"You totally are," Penny giggles.
6. Leonard discovers something in the sofa.
He's cleans the living room one night after work, before the gang comes over to watch the new episode of Doctor Who. Leonard lifts up a sofa cushion to dust it and spies something red balled up underneath. He picks it up and holds it up to the light. It's a pair of silk women's panties. Unless he's very, very mistaken, he's pretty sure it's a pair of Penny's panties. He dimly remembers her wearing them once.
The truly peculiar thing is that Leonard can't remember ever removing Penny's panties on his couch.
Huh, he thinks, balling up the panties and shoving them in his pocket. Huh.
He makes a note to ask Penny about it later but by the time she shows up that night, bags of Thai food in her hands, he's forgotten all about it.
7. Raj notices something odd.
Raj sits down across from him in the cafeteria. "I have to tell you something crazy," Raj says in a low, conspiratorial voice, his eyes scanning the room.
"What's up?" Leonard says.
"Dude, last night I happened to be driving by the comic book store and I saw Penny's car parked outside."
Leonard shrugs. "So? I had to work late, so Penny picked Sheldon up. It was New Comics Wednesday."
"No, no, wait," Raj whispers, leaning in close to Leonard. "I saw her car, and I swear I saw her and Sheldon kissing."
"What? No, you couldn't have seen that right," Leonard says. The math is simple. Sheldon plus Penny does not equal kissing.
"I only got a glimpse, but I'm still pretty sure that's what I saw."
"Raj, that's just not possible. He must have been getting gum out of her hair or giving her mouth-to-mouth resuscitation. She probably choked on her Slurpee or something."
"Yeah, you're probably right," Raj says, with a little laugh. "I mean, Sheldon and Penny? Kissing? In what universe would that happen?"
"Not in ours," Leonard says and both guys laugh at the absurdity of it all.
8. The weirdest thing of all happens.
Leonard wakes up early on Saturday morning and gets dressed. Out in the living room, he finds Sheldon on the couch, playing Mario Kart.
"I'm going to go get my hair cut, pick up some bagels," Leonard tells Sheldon.
Sheldon grunts something in return and Leonard heads out the door.
He drives to Supercuts and is surprised to find that it's closed. "On vacation," says a sign on the door.
Damn. He only trusts Tricia at Supercuts to know what to with his dense, curly hair. He'll just have to wait another week. He gets back in the car and drives to Noah's Bagels and buys a dozen assorted bagels and even a container of cream cheese, even though he can't eat it himself. Despite the haircut disappointment, Leonard's in a generous mood. The sun is shining and it's a beautiful day, perfect paintball weather.
Back at home, he climbs the stairs to the fourth floor, unlocks the door and opens it to see…
He opens the door to see Penny straddling someone on the couch. Penny's straddling a man on the couch and that man is Sheldon.
Oh, and they're both naked.
Did he mention that they're both naked and appear to be having sex?
Because they are. Really good sex, if the noises they're both making are any indication.
Leonard backs out of the living room into the hallway and shuts the door.
And that's the precise moment when Leonard begins to suspect something is going on with Sheldon and Penny.