A quartet of shows are having their final performances on Broadway today. Two of them, Accent on Youth (starring David Hyde Pierce) and The Philanthropist (starring Matthew Broderick), produced by Manhattan Theatre Club and Roundabout Theatre Company, respectively, have finished their limited runs. But Irena’s Vow and August: Osage County were open-ended Broadway runs that are only concluding now because of low ticket sales. August has had an unusually successful run for a Broadway play, having begun its highly acclaimed limited engagement at the Imperial Theatre in late 2007, then transferring to the Music Box Theatre so that it could enjoy a continuing run (winning the Tony Award and Pulitzer Prize for author Tracy Letts along the way). Unfortunately the show is closing shortly after Phylicia Rashad took over the major role of family matriarch Violet, a part that has already earned her raves from many of the audiences who have had a chance to see August in the last few weeks.