There's an emerging movie genre that's been gaining steam over the last few years—the hybrid of the action flick and the romantic comedy—as evidenced by two releases this winter alone: Knight and Day and Killers. The idea seems to be that a movie that's equal parts romance and action will cross gender lines and sell more tickets. Whether or not that's true remains to be seen, but I'm taking a look at some of the films that define this category of love and living on the edge.