S9, E21: Frasier and his family head to Boston for a business conference. They get sidetracked into reuniting with the old `Cheers' gang on the occasion of Cliff's retirement party, prompting everyone to recall many embarrassing memories. While Niles is bored, Martin hits it off with fellow beer-meister Norm. Carla can't wait to bid adieu to Cliff, but the postman has something to confess to Frasier.