Krispy Kreme Doughnuts to celebrate National Coffee Day with free coffee and doughnut for its guests on Sept. 29   WINSTON-SALEM, N.C., 2016-Sep-26 — /EPR Retail News/ — Krispy Kreme Doughnuts today announced that participating shops in the United States and Canada will celebrate National Coffee Day on Sept. 29. Any guest who visits a participating shop on…