From "How I Met Your Mother: The Stinsons (#4.15)"
Now that you mention it, Barney did do something kind of odd at the office yesterday.
[Flashback, Barney on the phone
] Okay, see you Saturday. I'm thinking brunch, farmer's market, maybe a hike. I love you, too. Bye.
I figured he was just talking to some girl he was trying to nail. Or Ted.