Cruel Intentions

A thoroughly modern update of Dangerous Liaisons and Valmont, here we have Kathryn (Sarah Michelle Gellar) making a bet with her step-brother, Sebastian (Ryan Phillippe) that he will not be able to break down the resolve of a virgin (Reese Witherspoon) who plans on remaining that way until marriage.

If Sebastian wins, he gets to have the one girl he has never been able to have -- his step-sister. If his step-sister wins the bet, she gets the keys to his classic Porsche.