Quote from Ted in The Final Page (Part 2)
Robin: Okay, what's the real reason Barney's not coming? Future Ted: [v.o.] Here was my chance to tell Robin about Barney. Ted: Yeah, actually, Barney didn't say what he was doing tonight. Anyway, uh, you know, I'm not taking anyone to the opening, so you want to be my date? Robin: Sure.