This ensemble-cast coming-of-age film showcases some young talent but is only mildly entertaining and finally forgettable, falling far short of the feel-good nostalgiafest it attempts to be. "Now and Then" centers mostly on "Then," telling the story of four girls on the brink of puberty who spend a summer experimenting with a Ouija board, playing Truth or Dare, engaging in a flirtatious rivalry with a group of neighborhood boys and overcoming personal dilemmas. The film is bookended with the "Now," opening with a brief profile of what each girl has become and closing with a return to the present, intended to show that the impact of that one summer remains with each of them 25 years later. The adult characterizations are so sketchy, however, that the point is not effectively made. The focus being spread over eight characters (counting both child and adult incarnations) diffuses interest in or connection with any one person. Gaby Hoffmann ("Sleepless in Seattle") as 12-year-old Samantha, an intelligent, individualistic sci-fi buff who is emotionally torn up by her parents' separation, is the standout; Melanie Griffith as the elder version of the vain but ultimately caring and supportive Teeny is the only jarringly bad performance, as she is unable to transcend her stock squeaky-voiced dim-bulb persona. Janeane Garofalo and Cloris Leachman have fun with their cameos. Starring Christina Ricci, Gaby Hoffmann, Thora Birch, Ashleigh Aston Moore, Rosie O'Donnell, Demi Moore, Melanie Griffith and Rita Wilson. Directed by Lesli Linka Glatter. Written by I. Marlene King. Produced by Demi Moore and Suzanne Todd. A New Line release. Drama. Rated PG-13 for adolescent sex discussions. Running time: 102 min.