(BILLY, a teenage boy, is sitting at the kitchen table playing Gameboy, but one of the new Gameboys that's not called "Gameboy". TABITHA, BILLY's grandmother, walks into the room)
BILLY: Oh! Hey, Grandma. How are you?
TABITHA: Billy, I've got something to tell you.
BILLY: What's up?
TABITHA: Please, put the game down, dear. I... This is rather important.
BILLY: (pausing Tetris or whatever) What is it? Is something wrong?
TABITHA: No, nothing's wrong, but... Well, I don't know exactly how to put this... Billy, you know you're very special to me, no matter what?
BILLY: Aww, Grandma...
TABITHA: Billy, I've watched you grow up over the years from a little boy into a fine, wonderful young man, and I think you're ready to hear this now.
BILLY: What is it, Grandma?
TABITHA: Well, Billy, the truth is, though I'll always love her more than anything... Your mother isn't actually my daughter.
BILLY: What do you mean?
TABITHA: After I married your Grandfather, God rest his soul, we wanted nothing more than to have children of our own, but the doctors told us we weren't able to conceive, so we talked to an orphanage and adopted your mother.
BILLY: So wait-- so that means you're not my real grandmother?
TABITHA: Well dear, technically speaking, no, I'm not.
BILLY: So we're not related at all...
TABITHA: No... No, we're not...
(cut to BILLY and TABITHA making love on a king size canopy bed. Two French doors are open, leading to a balcony filled with flowers and a sky exploding with fireworks. Music: an orchestral version of any Coldplay song)
(note: 99% of credit/blame goes to Zach Howard, from whom I stole the idea more or less completely)