Our COR girl this year (who's now VPR and rocks so much!) came up (with the help of our LC, Jillian, I think) to turn COR into a competition. She split the chapter up into teams and they all tried to get girls out to events...like if they get a girl to come out to an event they get one point, if a girl pledged they got like ten points and at the end the winning team got some kind of prize.
It worked pretty well, our girls got pretty psyched up about it. If you want I can try to find the "official" rules and type them up for ya.