Co-creator and exec producer Carter Bays agreed to answer a few of our queries.Given the fact that we've known from the start of the season that they end up getting engaged, we felt like Barney winning Robin had to be wrapped in something big and surprising. And Barney has gone to such great lengths to successfully seduce so many women, it felt like anything less than spectacular would be a disservice to Robin. Also, we liked the idea of a long con. I think the final run of episodes in season four of Breaking Bad was a big influence. We wanted a moment of, "Ohhhhh, that's what's been going on." Just without anyone getting blown up or poisoned.We're not blind to the possible ickiness of how Barney went about getting Robin to say yes. And neither are the rest of the characters. It'll come up that there's two sides of this coin: Was this a big, whimsical romantic gesture, or was it emotional manipulation? Ultimately, I think that's really Barney in a nutshell: loveable amorality. The next chapter in this story is about Robin deciding if that's really what she wants in a husband, and Barney deciding if he's about more than just magic tricks.It was the summer between seasons five and six, and after that there wasn't really any doubt. We built the last two seasons around the reveals of Barney getting married, and then Robin getting married. It felt right, for Barney and Robin, but also for where we hope to go with Ted's story.Part of Barney's scheme was making sure he had Ted's blessing, even if he had to trick him into giving it to him. Is this also a defense against the notion that Ted is a wuss for urging Robin to go after Barney? You're basically saying, "This isn't Ted being nice. This is Ted realizing Robin isn't his true love."I think sometimes wussiness and niceness are so confoundingly tangled up that it's hard for people to know what their own motivations really are. Ted wants Robin, but he also wants Robin to be happy. Both urges are enormously strong. It's a complex moment for Ted, and there's not really an easy answer.In some ways this episode was as much about Ted as it was Robin and Barney. Our hero is looking damn pathetic at the end of this hour: Now, every one of his four best friends has found happiness. We know Ted finds The One, but how quickly will things move now toward that resolution? You've got anywhere from 12 to 36 episodes left in the show; no matter the final number, can Ted stay this low for long?The short answer is no, he can't. This current condition will lead him down some unexpected paths, and he's not going to sit around and mope for the rest of the series. I think the honest human reaction to a situation like what Ted's in is to charge headlong into a terrible relationship that's absolutely wrong for you. And that's exactly where Ted's headed.That question has been coming up for eight years now, and our answer never changes. I don't want to seem unnecessarily opaque, but we're just never going to announce that. We're going to tell the story we set out to tell. I hope it's all right with everyone that we don't divulge huge spoilers for our own show. I get it. I get the frustration. It's a frustration that's built into the DNA of the show, and very much shared by its protagonist. You just have to wait and see.Yes, advance notice is crucial, and so far everyone's been taking that very seriously. In my mind, the cliff is the TCAs in January. We'll be able to announce something by then.Ashley plays a love interest for Ted, who is wrong for him in a very funny way. Rachel and Ray will be showing up as well, though I'd rather not get into when exactly they'll be appearing. And just to be clear, that's Rachel and Ray. Not Rachel Ray. Rachel Ray will not be on the show as far as I know.We'll have a new Robin Sparkles episode on February 4. And by the way, that episode will be a big huge giant monster, for a bunch of reasons. Definitely the most astonishing lineup of guest cast we've ever assembled for one show. There's a lot more info to come on that one.I think you could make the case that the past eight years have been Barney's bachelor party. But yeah, I'm sure there's a hotel room and some dead hookers in Barney's immediate future.Tonight we watched as Ted struggled to decide whether to tell Robin about what was really going on between Barney and Patrice. But at the end of the day, Robin got the answer — or rather the question — straight from the source. As snow began to fall on a candlelit rooftop, Barney finally (finally!) proposed to Robin. Series costume designer Reiko Kurumada told EW that it was such a big moment in the show’s history, she wanted to make sure the characters looked unforgettable.“As as soon as I got the script, I had this vision of what I wanted Robin to be wearing. I really just wanted a classic, simple, gorgeous gown. I looked high and low, different department stores, different designers, and I couldn’t find the perfect gown,” Kurumada remembered. “We were getting down to the nitty gritty, so I decided to look on Monique Lhuillier’s website and there it was. That was the gown!”Kurumada — who has made major changes to Robin’s wardrobe since taking over as head costume designer — didn’t want to distract from the character’s show-stopping red dress, so she accessorized the look with a pair of simple faux diamond Nadri earrings and an Alice + Olivia coat. “We did a bunch of alterations,” Kurumada said of getting the jacket just right. “Initially, it had a tie belt, but we took it off and tailored the back. It turned out to be exactly the vision of what we wanted.”Of course, the ever-stylish Barney suits up for the big moment, donning Dolce & Gabbana and his classic Burberry overcoat. But this time he had a new trick up his sleeve.Although we’ve already gotten a sneak peek at Robin’s wedding gown, which is also from Monique Lhuillier, Kurumada said we’ll definitely get another glimpse of it in the near future.But even before the episode had hit television screens, executive producer/co-creator Craig Thomas knew it was something special.“I was on set for [the limo scene with Ted and Robin], and it was just one of those moments where you feel really lucky to work with these actors — and everybody,” he says. “It was just one of those moments where you’re like, ‘Well, you know, the show isn’t going to last forever. So let’s just take a moment while filming this to appreciate the depth of this cast and how much we care about these characters eight years in.’”But even eight years in, there’s still quite a bit of story to tell. For scoop on tonight’s developments and a look ahead, read more from Entertainment Weekly’s chat with Thomas below.: Josh [Radnor] and Cobie’s limo scene was one of those where it so much more powerful than you thought it’d be. That moment with Cobie and Josh, in a sense, was Ted was saying goodbye to Robin and saying goodbye to the possibility of getting her. He makes that sacrifice and supports her so she can go make one last Hail Mary pass for Barney. It’s almost saying goodbye to a whole future possibility that, in the back of his head, he always imagined. He knows it and she knows it. It’s like eight years of history sitting there between those two characters in that limo, and it was just really heartbreaking. It really hit them; they both started to cry. We weren’t pushing them to cry. It wasn’t written, ‘Now they cry!’ It just really hit them. So what you’re seeing there is them feeling that for their characters. It was just a real reaction that no one asked for and surprised everybody.But it was an important moment for Ted to finally get there.Then, Ted was an amazing friend to both Barney and Robin in that moment, but then seeing Ted standing alone there by that window looking out at the world and looking ahead, it’s definitely bittersweet. There’s a wistful feeling about it at the end. There are about five different moments in the episode where we all started crying. We’ve seen it 100 times now, and it keeps getting us. So hopefully everyone will like it.Yeah. Definitely there’s a feeling at the end of the episode [that] there’s still an odd man out here. There’s still Ted Mosby, who is just the best friend in the world to Robin and to Barney, and he’s still out there searching. There’s definitely a “to be continued” feeling. If Barney and Robin have gotten to the place we’ve always promised and are heading toward a wedding potentially, what’s in store for Ted? It’s a nice moment to end on. It sort of feels like a mini season finale even though it’s just a midseason finale. It feels like, “Alright now, let’s see what the next — and possibly last — chapter is for Ted.” How does he move into his future if we are watching Barney and Robin move into theirs? In the way that Christmas is sort of great and a little bit sad and nostalgic and wistful — that’s definitely how I feel at the end of the episode. And hopefully people will feel a feeling of resolution, in terms of waiting for Barney and Robin to reunite, but also a question left unanswered. Stay tuned for what either will be the final 10 episodes ever of the show or possibly that plus one more final season. We don’t know yet.Right. They’re heading for a wedding that will have its own twists and surprises when we get there. But yeah, we’ve been waiting for them to get engaged, so hopefully that will feel satisyfing to people. It certainly has been a long time coming.To me it feels like a really appropriate way for Barney to propose to someone. We could have gone much straighter at it and had just had him propose in episode 3 of this season, but there’s something really fun, elaborate, playbook-y, and very “evil genius” about the way Barney put it together. [Laughs] He’s an evil but very sweet genius, I suppose. It’s very heartfelt and wonderful. The moment where he’s on bended knee and puts a ring on her finger is just super sweet. I hope people will be as moved by it as we were making it.We loved the idea of the secret last page of the playbook. Barney Stinson is Barney Stinson, and he wouldn’t propose in some predictable way. We also liked indicating that there’s one last great play for Barney Stnson to execute, and it sends him into this whole next chapter of his life — a new, more evolved part of his life. But I still like that the thing that catapults him into the next phase of his life is a play from the playbook — the secret final page. It’s the last play he’ll ever run, and it’s the last play he’ll ever need to run because it’s going to get him the love of his life. It felt like a good way for Barney to be Barney and still get engaged, which is a pretty high degree of difficulty. We’ve also seen these two characters come together and pull apart a few times, so the challenge we tried to set for ourselves was how to get them back together in way that felt unlike what we’ve done before.Exactly. We’ve been tell the story of how Barney is imagining this future and imagining being able to do this. It just wasn’t the right girl. Robin was the right girl for him, and we needed to connect the dots.It does feel that way. The series could end this year, and Barney will be engaged. You’re not going to see [another] episode where Barney Stinson is single and out there and running plays from the playbook and finding elaborate ways to have meaningless one-night stands. So we like the idea that Barney would use his superpowers and his Barney-ness for good instead of evil and see that his Barney-ness is what gets him the love of his life in the end. It felt poignant in terms of the journey we’ve seen Barney go on throughout the series.Barney is still Barney. So we’ll see what it’s like for Barney Stinson to really be engaged and really know that “This is the last woman I want to be with.” We’ll see Barney struggle with reconciling those two parts of himself– the playboy manipulator and the guy who’s got the girl. How does he behave and make sure it all goes well? Ultimately, it’s not going to be Barney constantly looking at other women and asking, “Did I make a mistake?” and angst and all that. It’s not that. We want these two characters to be together, and we know they’re heading toward a wedding day. So far it’s actually been fun; Barney is still fun. The challenge is that it forces you to tell new kinds of Barney stories and so far, episode 13 and 14 are really fun Barney episodes. In episode 13 we see Barney have to deal with Robin’s super scary father, who they forgot to ask permission from to get engaged. So we see them go through that process.Yeah. There’s going to be an appearance from Rachel Bilson, who we know is a very direct, one-degree of separation from The Mother. I don’t want to say too much more about that, but she will reappear. Make of that what you will.I literally can’t tell you much about that either because it’s a little bit of a twist. But she’s really funny, and the one thing I can tell you is that she will play a much younger woman who Ted is attracted to but he ends up asking the question, “Am I just way the hell too old to be up this late at a club with this girl?” It definitely forces Ted to ask the question, “Am I getting too old for this?” — for lack of a better term. But she’s going to be great. We’re shooting that as we speak. That’s episode 14.Yeah. So if this turns out to be our last year, we’ll come back in the new year and shoot just 10 more and that will be it.You and me both!I can tell you this, we’re going to do the final installment of Robin Sparkles. The fourth and final installment — witnessing a chapter in the Robin Sparkles saga that we’ve never seen. It’s sort of the ending chapter in what was the Robin Sparkles career.