The One In Barbados, part 2 - S9-E24
Visible crew/equipment: During Monica and Mike's game, after Mike makes the comment that Monica should look in the mirror before calling herself a girl, in the following wideshot after the closeups the camera/equipment can be seen at the right side of the screen.
The One In Barbados, part 2 - S9-E24
Other mistake: The layout of the hotel surrounding the main cast's rooms as displayed during the sequence where Monica, Chandler, and Phoebe eavesdrop on Ross, Charlie, Rachael, and Joey is physically impossible. Ross enters the room Monica, Chandler, and Phoebe are in through the same wall they are using to listen in on Charlie and him, though while the camera is in Ross and Charlie's room, no door can be seen in that wall. Furthermore, a hallway can be seen through the doorway while Ross holds the door open, implying that the two rooms do not share a wall in the first place.
The One In Barbados, part 2 - S9-E24
Visible crew/equipment: While Joey's wearing the snorkel gear he blows a grape out of his snorkel tube, and when Charlie walks into the room the opening in the wall can be seen beside the door.
The One In Barbados, part 2 - S9-E24
Continuity mistake: In the final episode of series 9 part 2 where Phoebe is talking to first David and then Mike the shot keeps changing. Each time it does the amount of hair down Phoebe's back changes from a little to a lot. (00:23:30)
The One In Barbados, part 2 - S9-E24
Character mistake: When Monica and Mike are playing table tennis, Monica puts her hand on the table and looses the point. Mike then does the same thing. Surely Monica, of all people would notice that as it would have given her the point. We also see her looking at Mike at the time. (00:33:40 - 00:39:25)
Suggested correction: Not really a mistake to not notice it, especially when it may be what a character like Monica would notice. She is being extremely competitive and frustrated because Mike just denied her a point, so it's fair to say human nature plays a part here.
The One In Barbados, part 2 - S9-E24
Continuity mistake: In the One in Barbados (part 2), just after Monica bashes her hand against the table, the shot of Chandler asking if she's OK shows Monica raising a finger right at the edge of the screen. We then cut to Monica, who's cradling both her hands together. (00:42:50)
The One In Barbados, part 2 - S9-E24
Visible crew/equipment: When Ross and Charlie are hiding behind the the plant the camera switches to a wider shot of the the three scientists looking around.When it does this the microphone is very visible at the top of the screen. (00:45:00)
The One In Barbados, part 2 - S9-E24
Visible crew/equipment: When Mike and Monica are playing ping pong after Mike says "do you wanna volley a bit for serve?" when the camera switches to a wider shot the microphone dips into view above Monica's head. (00:32:00)
The One In Barbados, part 2 - S9-E24
Revealing mistake: When Ross is talking to the weird obsessive scientist at the bar, just before the wife comes in, the wall behind the professor moves in shot to allow the cameraman room to swing around in the next shot. (00:40:20)
The One In Barbados, part 2 - S9-E24
Continuity mistake: In The One In Barbados, part 2, when Ross and Charlie are hiding behind the plant from the other scientists, the drinks they are holding refill themselves and Charlie's ornament in her drink keeps switching sides of the glass. (00:45:10)
The One In Barbados, part 2 - S9-E24
Continuity mistake: When Monica and Mike play table tennis and Monica says "I think that may have missed the table" there is no one sitting in the chairs behind her. The shot then cuts to Mike and he replies "oh do you?" The shot then cuts back to Monica, she replies "er, yeah" and there are suddenly two people sitting in the chairs behind her. Then in the next shot of Chandler and Phoebe the women who were just in the chairs are now walking behind Chandler and Phoebe in the direction of the chairs, and in the next shot they take their seats. (00:38:40)
The One In Barbados, part 2 - S9-E24
Continuity mistake: At the end of the episode, when Joey walks into Rachel's hotel room, he is standing in the doorway. However, when Joey and Rachel kiss, there is enough space for the door to close. (00:47:05)
The One In Barbados, part 2 - S9-E24
Continuity mistake: As Mike and Monica are playing ping-ping, two people playing checkers magically materialize behind Monica. One second they're not there and the next second they are. (00:12:25)
The One In Barbados, part 2 - S9-E24
Visible crew/equipment: Right before Ross' speech begins, as the camera pans down, if you look at the top of the screen, you would be able to see the top of the set and a set light. (00:31:20)
The One In Barbados, part 2 - S9-E24
Character mistake: When Mike and Monica are playing ping pong, Mike's service was a fault as he released and hit the ball over the top of the table rather than behind. He then (on the same point) claims to win the point because Monica placed her hand on the table. (00:33:00)
The One In Barbados, part 2 - S9-E24
Continuity mistake: In the scene where David wants to propose, when Phoebe and David get seated in the restaurant Phoebe puts her bag on the floor to the left of her chair. When there is a wider shot again, it has vanished. (00:25:25)
The One In Barbados, part 2 - S9-E24
Continuity mistake: At the end of the ping pong scene when Chandler wins, a paddle appears on the floor for one shot then disappears in the next. No-one had time to touch it. (00:44:20)