Continuity mistake: When Jan, Michael and Pam are having a meeting in Michael's office they're sitting against the front window, but during that scene when it shows Jim and Dwight talking at their desks, if you look over Jim's shoulder you'll see that the office behind them is empty. (00:06:30)
Continuity mistake: When Michael takes Katy (the purse lady) around the office, she worries about leaving her purses unguarded so while walking by Phyllis and Stanley's desk clump he asks Ryan to look after the purses, but Ryan says he can't because he's "installing File-Share on all the computers." Phyllis is noticeably absent from the shot. Ryan is sitting at Phyllis' desk. Michael and Katy take a few steps and walk into the kitchen area. In the background we can now see that Phyllis is now sitting at her desks and Ryan is nowhere in sight. There wasn't enough time for both to switch locations like that as only a moment had passed between the shots. (00:06:10)
Continuity mistake: While Michael is introducing Ryan to Dwight and the stapler-in-jello is found, we see that Phyllis' chair is empty. Then a moment later there's a shot of her looking at Jim while sitting in her chair with no time to get there. And then the chair's empty when shown again. (00:15:25)
Continuity mistake: Dwight is hiding in a box in the basement when Pam comes down to the basement and pretends to make a secretive phone call. As she does so the box that Dwight is hiding in changes position on the floor, presumably so that the camera can catch the holes that Dwight has made in the box in order to breathe.
Continuity mistake: During the basketball game just before Pam throws the jump ball, Stanley is seen standing over Pam's left shoulder. After she tosses the ball up Michael hits the ball mid-air over to Stanley who is now about 10-15 feet in front of Pam, with no time to logically get there between shots. (00:13:15)
Continuity mistake: When they're having the Diversity Day meeting Jim's chair can be seen over Michael's shoulder several times. In the beginning of the meeting the chair is pointed towards his desk, but when Kevin says that he remembers the Chris Rock routine and begins to recite it, you can now see that the chair is pointed towards Pam's desk; however no one has left the meeting in that time. (The only person who's not in the meeting is Devon. He was at his desk and walking around a few times but it makes no sense that he would go and move Jim's chair.) It's obvious that the actor left the chair in different positions during different takes. (00:06:00 - 00:07:05)