Sexual intrigue, Hellen Keller and urine; that’s what area theaters have to offer us during the slow month of August, the dead time between the close of the ’04/’05 season and the beginning of the new one. In all seriousness, August still has plenty of offerings for D.C. theatergoers, as a bunch of well-received shows take final bows and a few exciting new productions make their debuts. People can’t stop tinkering with Les Liasons…