'Game Night' - Season 1, Episode 15
After an old girlfriend drops off a tape of the "real" Barney, Barney regales the gang with a story from 1998 and how became the awesome Barney he is today.
Air Date: February 27th 2006.
Marshall: Backgammon sucks. I took the only good part of backgammon, the gammon, and I left the rest of it in the trash where it belongs.
Marshall: Well, we have the whole place to ourselves.
Lily: I'm thinking ... floor sex!
Marshall: Sounds reasonable.
Barney: Believe it or not, I was not always as awesome as I am today.
Victoria: Well boyfriends, I've only had two.
Robin: Prude alert!
Victoria: Well, that's serious boyfriends, I've dated other guys in between.
Robin: Slut alert!