All it takes to come out of your shell is to holler, "Stella!" That's what shy hardware store clerk Christopher Walken discovers as he is cast in the role of Stanley in a community theatre production of "A Streetcar Named Desire." Walken's character mightnever have stepped out into the stage lights if not for his "Stella," played by Susan Sarandon. This is a terrific tale based on the short story by Kurt Vonnegut, all about what you get when you take chances.