There aren't many drive-ins left in the Denver area, but judging from the lines that snake out from the entrance to the Cinderella Twin on weekend nights during the summer, there's still plenty of demand. This south metro area drive-in boasts two screens, each showing a double feature -- PG for the early show, R-rated later -- a full-dinner snack bar, FM radio sound in addition to traditional in-car speakers, and free admission for kids under eleven. And as the only local drive-in that runs during the spring -- it opens the weekend before Easter -- the Cinderella Twin also offers a nice place to cuddle: Special early-season deals, including in-car heaters and a $12 per carload price, last until May.