On May 23, the New-York Historical Society Museum & Library, at 170 Central Park West at 77th Street, kicked off its observance of Stonewall 50 with a festive reception and dance, featuring special guests and live performances, cocktails and hors d’oeuvres. Former Manhattan Borough President Ruth Messinger, Rollerena, Betty, and pianist Dan Daly, playing Cole Porter’s piano, were among the notables spotted there.