How I Met Your Mother (HIMYM) was on prime time TV for nine seasons and 208 episodes, making it one of the most successful sitcoms of the last decade. The show follows Ted Mosby (played by Josh Radnor), his married best friends Marshall Erikson and Lilly Aldrin (played by Jason Segel and Alyson Hannigan), womanizer Barney Stinson (played by the seasoned Neil Patrick Harris), and sometimes lover, sometimes friend, Robin Scherbatsky (played by Cobie Smulders), on Ted’s years-long search for his soulmate in a Friends-esq style.

That Theme Song

The theme song for HIMYM is pretty iconic as far as theme songs go—it’s up there with the Friends and Breaking Bad theme songs. The ease of recognition of the song makes sense as HIMYM is currently edging its way onto the list of most re-run shows on TV. And it turns out that the quick, peppy song, performed alongside flashing group pictures, was designed as a perfect fit for the show: it’s written and performed by The Solids, co-creator Carter Bay’s and Craig Thomas’ band. “Hey Beautiful,” wasn’t the band’s first successful theme song either, they also wrote and performed “The Future is Now” for TV’s Oliver Beene.

The Show Was Not Filmed In Front Of A Live Audience

HIMYM is a true sitcom, but is also a sitcom with a slightly unusual format. One of the things that makes the show so fun, and so loved by its fans, is its constant twists and turns. Things are often shown out of order—you’ll be in a flashback without realizing it’s a flashback, or they’ll show the same series of events from several perspectives. Flashbacks, and flash-forwards, and multiple perspective story lines can even last over multiple episodes. Because of its unusual formatting, the show, unlike most other sitcoms, was not filmed in front of a live audience. Instead the completed episodes were shown to a select audience, whose responses were recorded and used to fill and create the reaction track in postproduction.

Those Hidden Pregnancies

During the course of the show, both Alyson Hannigan and Cobie Smulder were pregnant with their first children. Not wanting to write either actresses’ pregnancy into the plot, creators instead tried to disguise them with some traditional TV tactics: flowy outfits, big purses, large props, and strategic blocking. These strategies worked well for Smulder’s pregnancy, but Hannigan’s proved a bigger challenge to conceal. At one point, the creative team used Hannigan’s pregnancy in a joke—in “The Possimpible” (season 4) her protruding baby bump is the result of winning a hot dog eating contest—and when Hannigan left for maternity leave, they had to find a way to explain away her absence, pinning it on her anger at a disgusting joke Barney told.

Many Spouses And Family Members Of The Cast Guest-Starred

HIMYM saw a lot of guest stars over the years. Everyone from Britney Spears to Tim Gunn to William Zabka made an appearance over the show’s nine-year run. But some of the weirdest guest characters went to the gang’s actual family members. Cobie Smulder’s (Robin) husband Taran Killam played Gary Blauman, Marshall’s co-worker at AltruCell and Goliath National Bank. Alyson Hannigan’s (Lily) husband Alexis Denisof played Sandy Rivers, Robin’s co-anchor, archnemesis, and sometimes love interest. And finally, David Burtka, husband to Neil Patrick Harris (Barney), played Scooter, Lily’s high school boyfriend whose love for her never died and whose dreams to be a baseball umpire never came true. All characters were so weird and quirky, and played with audiences so well, that they were written into multiple episodes over the run.

That Backup Mother

One of the major worries for new shows is cancelation. When HIMYM was picked up, the studio ordered 13 episodes (if those did well, then an additional nine would be added to complete the first season). And even after they successfully made it through the first season, there was still a strong worry that the show wouldn’t find its stride, a worry that was amplified by the low ratings. As a precaution, creators chose a backup mother and a shortened version of the storyline to fit her. Who was the backup mother? Victoria. Ted and Victoria met in season 1, and creators had a version where she could be the mother by the end of that season, or, if necessary, could come back in seasons 2 or 3 to be revealed the mother. And while Cristin Milioti is the perfect mother, Victoria has been voted Ted’s favorite, non-mother, girlfriend, so it’s safe to say that fans would have been okay with this alternative resolution.

The Website’s Became Real

The show really capitalized on other forms of media to boost their fan base and to keep viewers interested and engaged. One innovative way they did this was by creating tie-in websites that were mentioned by the characters. That’s right—every time Barney or Ted (or any of the rest of the gang) mentions a website, the show’s crew had already created it and sent it live. Most of the websites are incredibly in-depth and developed, with jokes from the show and little trivia facts sprinkled throughout. Some of the highlights are Barney’s blog, tedmosbyisajerk.com (thanks to Barney’s lie), and the Goliath Bank website, but you can also find an entire list of tie-in websites here.

The Bar Was Inspired By A Real Bar

MacClaren’s is the second most used set on the show, with the first being the apartment above. And while their bar is a set on a backlot of an L.A. studio, it’s based off of a favorite spot of creators’ Carter Bays and Craig Thomas— McGee’s Irish Bar in NYC. The duo spent long nights writing and drinking beer at their NYC haunt when they were still working on The Late Show, and when they were developing the sitcom, they decided their characters should have a similar watering hole to pass the long nights in. MacClaren’s namesake has since really capitalized on their fame: creating a HIMYM drinks list, running trivia nights about the show, and hosting the cast for drinks.

That Allergy

Early on in the show, one of Robin’s defining characteristics, beyond her nationality and fear of commitment, is her gang of dogs. She lives in her Manhattan apartment with at least five different pups (an impossible feat in real-life Manhattan). But in season 2, after she begins dating Ted, all the dogs disappear to live on a farm upstate. This seems a little out of step and out of character with the Robin we knew then, but it turns out the sudden change may have had a more real life cause than we knew. Actor Josh Radnor is actually allergic to dogs, something the producers didn’t know when they began shooting, and it would have been too much for his health to be constantly filming around all those dogs.

That Bro Code

The Bro Code is an integral part of the overall story in HIMYM. Barney’s religious adherence to it puts him, and the rest of the gang, in some crazy situations, and it almost thwarts his chances at marriage with Robin. But, according to Google, the bro code didn’t truly exist until Barney brought it onto the scene in 2008—making Mr. Stinson its actual inventor, which is a crazy feat for any TV show when you stop to think about it. Today, The Bro Code (written by Barney Stinson with help from a secondary author) is a real-life, bound book and can be bought at most retailers. You can pick it up along with Barney’s second most famous work—The Playbook.

NPH Is A Trained Magician

Magic is another large part of Barney’s persona. His abundance of magic tricks throughout the show are a never-ending annoyance to the gang, and his slight of hand abilities play a big part in his engagement to Quinn in season 8. But, as it turns out, those feats were easy tasks for Neil Patrick Harris since in his free time, Harris is actually a talented magician. As president of The Magic Castle Club in L.A., Harris frequently performs (he’ll often pull out a trick during award shows and interviews) and in 2006, he won the Tannen’s Magic Louis Award. After uncovering his unusual hobby, writers and directors chose to spin it into an ongoing gag, forcing Harris to keep his game up.

That Blue Horn

HIMYM was a prop-heavy show, in that a lot of the main plotlines are built around various props rather than places or actions. There’s the blue French horn from the pilot and the mother’s yellow umbrella, Lily’s paintings, the swords on Ted and Marshall’s wall—the list goes on and on. That prop closet had to be bursting at the seams by the end of the show’s nine-year run, and surely there are tons of fans willing to shell out thousands of dollars for a little piece of TV history, so what ever happened to those iconic items? Apparently, the cast and crew took home most of the big ones as parting gifts after the show wrapped. Josh Radnor got the blue horn, Neil Patrick Harris took home the original bro code and the group’s booth from MacLaren’s, and the director and two producers each took home a yellow umbrella.

That (Real) Engagement

The end of season 2 holds lots of relationship changes for the group—Lily and Marshall finally get married and Ted and Robin break up. One of the major plot lines in the two-part finale is the mistaken engagement (the erroneously delivered champagne with the ring in the bottom, and the poorly given answers) that results in Ted and Robin’s separation. But, in the spirit of the show, the engagement that follows the correct delivery of the ring was actually real! It turn out that it was all an elaborate favor for one of the writer’s friends, who actually wanted to propose to his actual girlfriend (who was a big fan of the show). In rehearsals, the ring was given to another set of extras, but when the camera’s were rolling, the ring was delivered to Timothy Russo who got his entire scene stealing proposal caught on camera. Talk about perfect!

That Death

The show thrived off of its many, often unexpected, twists and turns. Unarguably, the biggest one of all is the mother’s death in the finale. And while it caught many fans off guard, there were some members of the cast who had known all along. Josh Radnor, who played Ted Mosby, had known since season one, when all of the reaction shots with his future children had been shot. He’d held out hope that producers would have a change of heart by the end of the run, but ultimately had to watch his character lose what he’s fought so hard to find. Alison Hannigan also knew from early on that the mother was going to pass away, deeming the seasons long story telling extra “sweet” for that reason.

Those Kids

Ted’s kids, played by actress Lyndsy Fonseca and actor David Henrie, to whom he’s telling the story, appear in a handful of episodes (65 of the 208), looking exactly the same every time they’re on screen. It turns out that all of their appearances were shot during the first season to avoid having to explain away their inevitable growth and changes due to puberty. The directors had them film a handful of generic reaction shots that could be mixed in and used as needed throughout the series, which is why you see some of the same reactions twice throughout the shows’ run. But what about the finale? In the last two episodes, both kids have several lines that are key in wrapping up the story—is that just a coincidence? Nope, both kids knew how the show would end from season 1. The signed confidentiality agreements and kept the shows biggest twist a secret for nine years!

That Ending

Ending something that is so loved and has accrued such a massive following over such a long run is always a big task. The finale of HIMYM was no different, and while creative types on the show had long known how they envisioned the end, convincing audiences that they knew best was an uphill battle. The two-part finale is one of the most divisive in TV history: some fans loved that Robin and Ted ended up together and enjoyed the sweet aspect of the storytelling, while others felt the ending wasted and ruined everything the show had been building towards. Those that hated the ending had such strong feelings that the alternate ending didn’t appease them, that they started a petition to have CBS change the end of the show. The petition fell about 3,000 signatures short, and the ending remains, for better or worse.