My experience is very like cheffie's - I faintly remember barn dances in the 60s, and I remember them being replaced in the mid-70s by near-identical events (perhaps with a bit more attention to authenticity, for good or ill) called ceilidhs. The situation's complicated by the echt-Irish overtones 'ceilidh' has acquired more recently; I'm not sure what overtones 'barn dance' has.