"Party," suggests a cheerier, mid-90's update of Mart Crowley's "Boys in the Band." The guests at a soiree devoted to an elaborate variation of the game Truth or Dare represent the same narrow cross section of middle-class, Manhattan-based gay white men that inhabited Mr. Crowley's play. The mood of Mr. Dillon's play, however, is much more buoyant. If the stridently witty chatter in "Party" recalls "The Boys in the Band," the homosexual self-loathing that seeped through the earlier play has dwindled into an undertone. The group portrait presented by the play suggests a Christmas-card snapshot of a happy extended family.