So Barney and Robin slept together...I think it was expected. Luckily, they didn't keep with the sitcom cliche of keeping it a secret from everyone for months (something that has popped up more frequently since Chandler and Monica hid their affair in Friends). Robin and Barney agree not to tell anyone, to keep things normal, but they both let it slip; Barney to Marshall, and Robin, surprisingly, to Ted. Barney enlists Marshall's lawyer skills to find a loop-hole in the "Bro Code" so he doesn't feel so bad about sleeping with Robin. To Barney's dismay, Marshall insists that the code is "iron clad" and says that Barney needs to confront Ted. Barney and Marshall think about whether or not Ted as withheld the "Bro Code", and find that Ted has followed every rule. Meanwhile, Robin takes care of that problem when she guiltily lets it slip that she and Barney slept together. Barney picks up Ted for his "surprise" birthday party on the roof and tries to take him to Vegas to get him in the good mindset before Barney tells him the truth. However, Ted reveals that he knows about him and Robin, and says he's not mad, weirded out, but not mad. This was a trick (a pretty mean one for Ted) and Barney learns that Ted feels he has outgrown Barney. Ted says he doesn't want to be Barney's friend anymore. While all of this is happening, Lily, Marshall, and Robin are all on the roof (with the goat) discussing what happened with Barney. Ted shows up with the party, without Barney, and the story ends. In about a thirty second clip at the end of the episode, Ted begins to explain how the goat (Lily had a farmer in her kindergarten class who was going to turn the goat to the butcher shop, Lily takes it to the apartment) ended up in the bathroom. Future Ted starts to explain that the goat locked itself into the bathroom chewing on one of Robin's washcloths, when he corrects himself by saying, "Wait hold on; Robin wasn't living here on my thirtieth birthday. When did this happen? Oh, wait, the goat was there on my thirty-first birthday! Sorry, I totally got that wrong" cuts to black.
Now, we have some theories about what Ted said: either, it's the dreadful truth, and Robin and Ted get back together for a period of time; or, hopefully and for reasons yet to be found, Ted and Barney have reconciled, Barney and Robin are a couple, and they are living with Ted. (Remember, Lily and Marshall have their own apartment.) We believe that this may be so because Ted doesn't say, "Robin was living with me on my thirty-first birthday" he says, "Robin was living here on my thirty-first birthday". We are hoping that this is the case. Barney and Robin will hopefully find their way to each other...and not just in bed. *crosses their fingers*