MacLaren's; Four Years Ago: Ted and Barney, wearing tuxedos, sip Martinis at the bar. Barney says: "How do you keep a girl from becoming your girlfriend? Simple: the rules for girls are the same as the rules for gremlins.... Rule number 1: Never get them wet." Well, that seems counter-productive. "In other words, don't let her take a shower at your place." Oh. Never mind. "Number 2: Keep them away from sunlight, i.e. don't ever see them during the day. And rule number 3: Never feed them after midnight -- meaning she doesn't sleep over and you don't have breakfast with her. Ever." Ted wants to know if brunch is cool. Barney scoffs that it is not.
Current Day; The Apartment: Barney realizes he's done all three things with Robin and wonders if she's his girlfriend. Marshall can't answer that. He's too busy feeling sorry for himself. "Just once, I wish you guys would call me on tuxedo night."
Hockey Game: The New York Rangers train their "Kiss Cam" on Robin and Brad. Their faces are up on the Jumbotron, and the audience chants for them to kiss. Brad suggests that if Robin kisses him and feels badly about it, she's meant to be with Barney. She agrees, so they stand and pucker up. But before their lips can meet, Barney appears out of nowhere and lays his hand on Robin's shoulder, moves her out of the way, and sucker-punches Brad in the face. Of course, Brad is about twice the size of Barney, so Barney's the one hurting from the punch. He cowers at the end of the next row down, whimpering like a baby. "Brad, we can't fight like this all night! We both got some good shots in. Let's call a truce!" Hee. Brad is far more gracious than he needs to be, and says it's never cool to kiss another guy's girlfriend. Robin and Barney go through their whole, Girlfriend, that's a bit much... denial shtick (which is starting to grate, so I'll spare you). Let's cut to....
MacLaren's: Lily says that since it's gotten to physical violence, it's time for "the talk." Barney's all, "Because of that? Come on. That's my thing. I'm always punching guys. Girls. I'll punch a baby; I don't care."
Columbia Lecture Hall: It's time for Ted's first class. He starts to write his name on the board and blanks on whether PROFESSOR has one F, or two. He starts to make the second F, but a helpful student shakes him off, so he deftly turns it into an E.