Ted: Well, lucky for us, someone at this table is skilled in the art of detection. Robin's upset. She and Kevin are having trouble. He cheated on her.
Lily: No way. Kevin's an honest, decent guy who never on his best day could pull a hotter chick than Robin.
Ted: Maybe Robin cheated on him. Maybe Robin is the dirty bird who slept with someone else.
Barney: I don't know, this pole-vaulting thing seems like a slam dunk to me.
Lily: Oh, it is so obvious. Barney. What is the name of that guy you worked with... Uh, Randy? It was Randy.
Ted: Wait a second. I just cracked this case. The little maple leaf onesie. It made her homesick. That's why she's so upset. She's not going home for Christmas. She wants me to invite her to Ohio.
Barney: [loudly] That's got to be it!
Lily: Either that or she slept with Barney.
[Ted and Lily laugh. Barney joins in with exaggerated cackling]