10 Best Big Bang Theory Running Gags Ranked

The meme-worthy zingers of "The Big Bang Theory" made it a pop culture phenomenon while it was on air from 2007 to 2019. But years have passed and audiences have spoken: With every "Bazinga," the show's grip on the cultural zeitgeist has only gotten stronger. Littered with recurring jokes, references and puns, it's clear that the sitcom has succeeded in carving its own space out in the psyches and hearts of its fans. As anyone who's ever knocked on a door three times and called the name of the person on the other side of the door can attest.

Which of these repeated jokes, however, proves to be the most legendary of the pack? Looper conducted a fan survey of the best "Big Bang Theory" running gags, and we got a good idea of where favors lie amongst viewers. Think of Sheldon's (Jim Parsons) spot on the couch, Amy's (Mayim Bialik) codependent love of Penny (Kaley Cuoco), and the sound of someone crooning "Soft Kitty," and you'll have a good idea of what's on this list. Here are 10 of the ten best recurring jokes on the sitcom ranked.

Howard Wolowitz (Simon Helberg) is notorious for two things before he married Bernadette Rostenkowski (Melissa Rauch): his pervy ways and his codependent relationship with his never-seen mother, Mrs. Debbie Wolowitz (Carol Ann Susi). Much like other never-viewed but always-heard sitcom characters — such as Carlton the Doorman (Lorenzo Music) in the 1970s sitcom, "Rhoda" — Debbie manages to make a huge impression on the audience with her controlling demands and endless nagging without ever showing her face.

Howard's mother becomes a running gag throughout the series, forever hovering just out of frame, represented by a flash of a woman in a pink muumuu, but never afraid to offer her advice. Howard yearns for freedom from their bond yet genuinely loves her, as does the rest of the gang.

It's a struggle that comes to a sad ending when Debbie passes away in her sleep during the Season 8 episode, "The Comic Book Store Regeneration," a tragic death that was inspired by the real-life passing of Susi. Howard and the gang gather to mourn Mrs. Wolowitz and collectively learn that she was much kinder to each of them than even Howard knew. Debbie's legacy is carried on by Bernadette, who uses her uncanny ability to mimic Debbie's shouting to get what she wants out of her husband.

When "The Big Bang Theory" was actively airing on CBS, you couldn't escape "Bazinga." While Sheldon himself rarely said the catchphrase after Season 3 — the show's writing team realized it was turning into a tired cliché – it's a word that fans of the show still connect to the series, and bazinga means more than you may realize. It became such an identifiable part of Sheldon's character that he's retroactively heard saying it as a child in "Young Sheldon."

Cooper comes forth with his first bazinga in Season 2's "The Monopolar Expedition." Sheldon uses it then — as he will in the future — to double underline that he's pulled a prank on someone and has delivered a stinging punchline. Naturally, his humor is so dry that it doesn't often register to his friends that he was trying to make a joke in the first place. More infamously, Sheldon says the phrase repeatedly while hiding from Leonard (Johnny Galecki) in a ball pit in Season 3's "The Einstein Approximation" as he has a meltdown related to his inability to solve a physics equation.

The final leftmost seat on Leonard and Sheldon's couch is forever known as Sheldon's spot — and woe betide anyone who actually manages to sit in said area without his permission. He guards it fiercely with tooth and nail, and his friends take great pleasure in messing around in that section of sofa, sending Sheldon into paroxysm of fury. In "Young Sheldon," his spot is in a similar place upon the Cooper family's couch.

Rarely, Sheldon will allow someone else to take his place on the couch. One good example of this is when — feeling a pinch of guilt because Howard has missed out on an opportunity thanks to him during Season 4 in "The Apology Insufficiency" — he allows his friend to take the throne. But Sheldon remains reluctant to let anyone else perch upon the seat. After all, as he says in the Season 10 episode, "The Cohabitation Experimentation," "This seat is the sovereign soil of my bottom!" Is it any wonder he gets so upset when Howard sits there naked to prove a point during Season 6's "The Parking Spot Escalation"?

Amy Farrah Fowler has few friends when she becomes a part of Sheldon's life in Season 3. That might be why she bonds so hard with Penny when they first meet. Her appreciation of her new bud borders on obsession initially, but eventually they become the female answer to Sheldon and Leonard's connection. Of course, Sheldon and Leonard haven't kissed each other, so perhaps their bond is a hair weaker.

Most of the laughs mined from this running gag comes from Amy's over-the-top ways with her bestie. From using primate bonding techniques to curry favors with her to sending her an oil painting featuring Penny grimacing in pain as a gift to claiming that their menstrual cycles are synced, there's no social barrier that Amy's unwilling to cross to prove her devotion. In time, Penny begins to reciprocate Amy's overtures and a real friendship is formed — but it takes a while. The ride there is what makes it so entertaining.

Sheldon Cooper is an extremely organized and rigid personality. He goes to the bathroom every morning at 8:00 a.m. and eats on a preplanned timetable as well. This comes up multiple times in the show, and though those around him often try to change it, he simply sticks to the status quo that keeps him comfortable.

Sheldon's weekly schedule runs this way: On Mondays, he has oatmeal for breakfast and eats Thai food for dinner. Tuesdays are for burgers, usually from The Cheesecake Factory, previously from Big Boy. He also hosts episodes of "Apartment Talk," one of his webchats, on this day. Wednesdays are new comic book and Halo play-through days, with no particular food assigned to the evening. Thursdays are generally pizza day during the run of the show — Sheldon's preferred order is sausage, mushrooms and a sprinkling of olives. Fridays are for Chinese food and vintage gaming. On Saturday, he has cereal while watching "Dr. Who."

Sundays are often left open for him, which is hilarious for such a strict schedule. Deviation usually plays havoc on his sensitive ecosystem, much to the frustration of those surrounding him, thus he remains stuck in his ways.

It only comes up a few times during the course of the show, but every mention gets a laugh. Penny is notorious for mooching off of Sheldon and Leonard, especially in the show's early days before she has a well-paying job of her own. She takes their food and steals their Wi-Fi, which leads to them changing the password frequently to hint at their displeasure with this development.

To wit: During "The Thespian Catalyst" in Season 4, Penny asks for the new password, and she'd told it's "pennyisafreeloader." By Season 5's "The Speckerman Recurrence" it's "pennyalreadyeatsourfoodshecanpayforwifi." Seasons later — after marrying Leonard and moving in with him — Penny jokingly tells a struggling Bernadette that you can always turn to your neighbors during hard times and try to get free food and Wi-Fi from them. The risk, Penny says, is that she or Howard might end up married to their benefactors.

A permanent sight gag in the background of every single "The Big Bang Theory" episode is the broken-down elevator in Sheldon and Leonard's apartment building, which is marked off with yellow caution tape. The audience is never told why it stopped functioning at first. It's revealed later in the show's run — during Season 3's "The Staircase Implementation" — that Leonard ruined the elevator while testing experimental rocket fuel. That incident resulted in Sheldon saving his life when the inevitable explosion went off. In spite of the fact that the group is laden with physicists and scientists, no one except Howard has tried to mend the elevator, and he immediately gives up his attempt — calling it a lost cause.

A number of the gang's guests try to use the elevator before learning it's out of commission. Sheldon, Leonard, and Penny sometimes pry open the elevator shaft and use it as a dumping ground for unwanted possessions — such as the time Leonard and Penny dumped their critter-infested Christmas tree down there in Season 10's "The Holiday Summation." Longtime fans were finally rewarded in the show's next-to-last-episode, "The Change Constant," where the elevator is fixed. It remains operational throughout the final episode, "The Stockholm Syndrome."

The lullaby "Soft Kitty" has become one of the most enduring pieces of "The Big Bang Theory" lore, a callback that has been used and referenced on "Young Sheldon" and "Georgie and Mandy's First Marriage." The simple tune is first sung during Season 1 in "The Pancake Batter Anomaly" by Penny to a sick Sheldon at his request, explaining that his mother used to sing it to him when he felt unwell. The bit of music is often subsequently used as a comfort measure between the two characters when either of them feels ill, lonely or sad.

Other people in their orbit soon pick up the song. Sheldon's mom, Mary (Laurie Metcalf), sings it to him in Season 5's "The Rhinitis Revelation" and Sheldon plays it for an ailing Professor Proton (Bob Newhart) in Season 6's "The Proton Resurgence." By the time Season 10 rolls around, Amy has learned the tune and sings it to Sheldon in three different languages during "The Recollection Dissipation." "Young Sheldon" eventually has Mary warble "Soft Kitty" to Sheldon as a child; it's a tradition his brother Georgie (Montana Jordan) uses while trying to get his own daughter to sleep in "Georgie and Mandy."

When they move in with each other, Sheldon and Leonard sign a long, voluminous and highly detailed roommate agreement in an attempt at trying to keep their household in order. Their requests, desires, and demands ultimately end up creating a convoluted covenant that goes through revision after revision throughout the run of "The Big Bang Theory."

Sample clauses include Section 27 Paragraph 5, which explains that the roommate agreement can never touch the ground. There are notes covering what they should do if artificial intelligence takes over the world, or if Sheldon must be Leonard's sidekick if the latter attains superpowers. More mundanely, Leonard has agreed to drive Sheldon to all of his important medical appointments, while Sheldon is required to ask Leonard how he's doing once a day.

These rules and their status as roommates undergo a yearly reevaluation, and in an undeniably iconic "Big Bang Theory" roommate moment, Season 4's "The Agreement Dissection," it's rewritten. It's never explained what happens to the agreement when Leonard and Penny and Sheldon and Amy marry and they split households, but the show never states outright that it's been dissolved.

Sheldon has a long-held habit of knocking on a closed door three times, then calling the name of the person he's looking for, then knocking again — a pattern he repeats three times. It is without a doubt the most quintessential running gag in the sitcom's history. It also happens to be an unscripted "The Big Bang Theory" moment, making its ultimate inclusion in the pop culture pantheon a stroke of sheer luck. Over the course of the show, both Leonard and Penny put up with this quirk, though sometimes they push back against Sheldon's neediness. When Amy enters the picture she, too, gets to hear her boyfriend's signature knock. He does it to other people across the span of the series, even Stephen Hawking in Season 6's "The Extract Obliteration."

In Season 10's "The Hot Tub Contamination," Sheldon explains that he started using this greeting pattern after walking in on his father and a mystery blonde having sexual relations. He subsequently refuses to enter a room without using this type of knock, saying that the carefully-spaced thuds give people enough time to put their pants on and disengage from their activities before answering his call. Sheldon never figures it out, but George Cooper (Lance Barber) never had sex with a stranger, or a protracted affair; the blonde was Sheldon's mother, Mary (Zoe Perry), in a wig. It turns out that his knock was developed for no reason, an irony he never discovers — but one that pushes this long-running reference over the top and makes it the best "Big Bang Theory" running gag ever.