Pnin's party was a failure. Nabokov took an aspect of life that is typically considered to be joyous and with it produced a negative outcome. Pnin is harassed in both confrontational and "behind the back" ways. Pnin learns later on that his job is in jeapordy which causes the party to become less and less of a celebratory event and more of Pnin's downfall. Nabokov likes to play with extremes, and although having unfortunate things occur at a party is not a revolutionary idea, I believe his (Nabokov's) intention was once again to depict the bad happening within the "good".