Xander:  Willow! You’re so very much the person that I wanted to see!

Willow:  Oh, really?

Xander:  Yeah. You know, I kinda had a problem with the math.

Willow:  Uh, which part?

Xander:  The math. Can you help me out tonight, pleeeease, be my study buddy?

Willow:  Well, what’s in it for me?

Xander:  A shiny nickel!

Willow:  Okay. Do you have ‘Theories in Trig’? You should check it out.

Xander:  Check it out?

Willow:  From the library? Where the books live.

Xander:  Right, I’m there! See, I wanna change…

Buffy the Vampire Slayer, Season 1: Episode 1 – “Welcome to the Hellmouth”