Before I begin this post, in which I attempt to cast Diablo Cody's Sweet Valley High, I have a confession to make: I, a man, maaaaay have read some of these books. Wait, I can explain! I have a twin sister, and she had all of them laying around when I was a kid. Also, I was a completely voracious reader back then, and I was like, "Hey, I'm a twin, and so are these characters! Perhaps I'll read one of these on a Sunday afternoon now that I've finished Dostoevsky." OK, also, I was gay. There's that.
Anyway, now that we've gotten that preface out of the way, let's own our quirks and attempt to cast this thing:
Characters: Elizabeth and Jessica Wakefield
Description: Elizabeth is the more studious twin who hopes to someday become a journalist (oh, the dreams of the 80's!), while Jessica is the flibbertigibbet cheerleader. As Wikipedia (and every opening chapter) puts it, they both have sun-kissed blonde hair, golden California tans, dazzling blue-green eyes, tiny dimples in their left cheeks, and perfect size six figures.
Ideal Actor: If she hasn't fled the Cody coop after the box office performance of Jennifer's Body, Amanda Seyfried would make split-screen hay of these roles. According to Cody, she's even posed for some of the books written by Francine Pascal, Sweet Valley High's creator.
Runners-Up: Taylor Swift, Emma Roberts
Character: Todd Wilkins
Description: Elizabeth's boring, hunky boyfriend who drives a motorcycle even though Elizabeth is not allowed to get on any motorcycles.
Ideal Actor: Taylor Lautner's got this part on lockdown. He loves introducing teenage girls to the exhilarating joys or motorcycle riding, especially if it means he can take off his shirt.
Runner-Up: Penn Badgley
Character: Lila Fowler
Description: The closest thing Sweet Valley High has to a mean girl, she's Jessica's fashionable frienemy.
Ideal Actor: So why not go full circle and cast from Mean Girls? I sense a comeback role for Lindsay Lohan! Who wouldn't thrill to the sight of Lila cooing to Jessica's face but then, once she was out of sight, composing a hard-bitten, nicotine-fueled Twitter kiss-off?
Runners-Up: AnnaLynne McCord, Sally Draper
Character: Bruce Patman
Description: Jessica's ex, a wealthy, arrogant tennis player. When she beats him at his own game he snots, "Who do you think you are, Chris Evert Lloyd?" Again: The 80's, folks!
Ideal Actor: Twilight's Kellan Lutz would be a perfect fit -- just don't book him for any Sweet Valley cruises.
Runner-Up: Chace Crawford
Character: Winston Egbert
Description: Winston's the class goofball, unafraid to try out for the cheerleading team if it means getting the joke.
Ideal Actor: This part calls for an improv-friendly actor who's in on the joke, so who better than Jonah Hill to riff on Sweet Valley High's cast of gorgeous hardbodies?
Runners-Up: Bo Burnham, Jesse Eisenberg
Keep going with your suggestions! I'm embarrassed to say how much more I know.