The Norman Conquests (Circle in the Square, 235 W. 50, closes July 25). Alan Ayckbourn’s 1973 comic triptych–three farces about adultery and its discontents, set on the same weekend in different rooms of the same house–is a jolting combination of laugh-till-you-choke lunacy and deep melancholy. This long-awaited Broadway revival by London’s Old Vic does it full justice. The three plays can be seen individually and in any order, but the best way to see them is in a single day-long sitting. Specially priced marathon performances of “Table Manners,” “Living Together,” and “Round and Round the Garden” take place each Saturday and on May 17 and June 28. Break the piggy bank and go while you can (TT).