This year is particularly good for David Mamet. His successful screen adaptation of his Pulitzer Prize winning drama, Glengarry Glen Ross, starring Jack Lemmon and Al Pacino, is touted as a serious contender for the Oscar Award. Mamet has also written the screenplay for the biopicture Hoffa, starring Jack Nicholson, which will open in December. His new Off Broadway work, Oleanna, a two-character play which promises to be a meditation on the political and sexual warfare, is now previewing in New York.