Barney: What could you possibly have to say for yourself?
[flashback to Ted and Margaret talking about acting tips:]
Margaret: Acting rule number one: "Don't be afraid to improvise."
[present:]
Ted: Was it me who betrayed you, or you who betrayed me?
Barney: I'm sorry. What?
[flashback:]
Margaret: Acting rule number five: "Invent a rich back story for your character."
[present:]
Ted: November 14th, 1998. The overnight train to Monte Carlo. I was in the billiards car hustling some Algerians out of few thousand dinar, when you seduced my fiancee! Who is blind and thought you were me.
Margaret: Yes.
Barney: What in God's name are you talking about?
[flashback:]
Margaret: Acting rule number eight: Don't be afraid to get physical.
[present:]
Ted: [slaps Barney] You know damn well what I'm talking about!
Barney: No, I don't!
Ted: [slaps Barney again] Yes, you do! And by God, I'll hear you say it, scoundrel!