Robin : "How do you do this, Ted ? How do you sit out here all night, on the roof, in the cold, and still have faith your pumpkin's gonna show up ?"
Ted : "Well, I'm pretty drunk. Look, I know that odds are the love of my life isn't gonna magically walk through that door in a pumpkin costume at 2:43 in the morning, but… this seems as nice a spot as any to just, you know, sit and wait."

Barney : "Every Halloween I bring a spare costume, in case I strike out with the hottest girl at the party. That way I have a second chance to make a first impression."

Barney : "You know what I love about Halloween ? It's the one night of the year chicks use to unleash their inner ho-bag. If a girl dresses up as a witch, she's a slutty witch. If she's a cat, she's a slutty cat. If she's a nurse…"
Lily : "Wow, we get it."
Barney : "…she's a slutty nurse. "