Quote from Barney in Weekend at Barney's
Barney: Exactly, Ted. You want to invite a date to our wedding, it is not gonna be Jeanette. It is gonna be someone new. And I am gonna help you find her with a little help from... [later, at MacLaren's:] Barney: The Playbook. Ted: The Playbook? Didn't you burn that? Barney: Oh, I didn't burn the real one. That was the ceremonial playbook for parades, mall openings, inaugurations, stuff like that. Ted: That's a pretty big secret to keep from Robin. Barney: Which is exactly why I'm trusting you, my best bro, to never let her know that the Playbook still exists. Pinky swear?