the office jim and pam first date episode
The seventh episode.
The Client (The Office)

The idea for Jan and Michael to have a romantic relationship was conceived by Steve Carell as far back as the filming of the pilot episode. The kiss between the two was rehearsed and filmed "many, many, many times", according to B. J. Novak. While filming, Steve Carell and Tim Meadows improvised a good majority of their dinner scene, but most of it never made the final cut. During the production of the episode, the cast and crew were informed by NBC that the show would be picked up for a whole 22 episodes, a move that "surprised" them. The episode received mostly positive reviews from critics and earned a Nielsen rating of 3.8 in the 18–49 demographic, being viewed by 7.5 million viewers.
wiki:21639402
The Client (The Office) [SEP] Introduction
"The Client" is the seventh episode of the second season of the American comedy television series "The Office", and the show's thirteenth episode overall. Written by Paul Lieberstein, who also acts in the show as Toby Flenderson, and directed by Greg Daniels, the episode first aired in the United States on November 8, 2005 on NBC. The series depicts the everyday lives of office employees in the Scranton, Pennsylvania branch of the fictional Dunder Mifflin Paper Company. In this episode, Jan Levinson (Melora Hardin) and Michael Scott (Steve Carell) begin a relationship after landing an important client (Tim Meadows). Meanwhile, the rest of the office finds a screenplay written by Michael and they decide to read it together.