Greg Bouljon and Mandy Landreth in SylviaChoosing a favorite line of dialogue from A.R. Gurney's Sylvia is nearly impossible, as the playwright's hysterically clever and insightful comedy offers almost too many choices; some of Gurney's best jokes here are so spectacularly subtle that you barely register them. ("Just close your eyes and think of England" is an especially sharp throwaway.)