Ramona Singer and LuAnn de Lesseps are taking the plunge off-Broadway. The drama-generating “Real Housewives” have signed on as producers of the “Fifty Shades of Grey” musical “Fifty Shades of F****d Up.” The unauthorized parody includes 14 songs that promise to “knock your socks or your pants right off.” Pictures on the Web site show the lead characters, named as in the book, Anastasia Steele and Christian Grey, flanked by masked, underwear-clad performers holding whips.