The Mary Tyler Moore Show - Season 4 Episode 15 Happy Birthday, Lou!

Lou is closing in on fifty and today is his birthday. Mary can't stand the thought of the now-separated Lou celebrating his birthday all alone, so she arranges a surprise party for him. That evening, she invites Lou over for a drink and the doorbell rings just as he tells her how much he appreciated her not throwing an office party for him that afternoon. Gordy is at the door with an envelope...full of hats. Others are out in the hallway, too. Lou is furious and tries to get out using the back door...but there is no back door. Mary asks Lou's permission to invite Murray in. He enters, miffed at Lou's actions. Next Rhoda, and finally Ted, get to come in. Lou admits that he hates displays of affection...then reluctantly agrees to let the remainder of the guests in. While they all file in, he files out and down to MacKluskey's bar where....they throw a surprise party for him. Later he returns to Mary's place to apologize...evidently the guests opened his gifts (at Ted's urging) and they a