The One With The Halloween Party - S8-E6
Continuity mistake: When Phoebe is talking to Ursula's fiance Eric, he is wiping sweat off his face with a napkin. He puts the napkin to his eye and then in the next shot it changes to the other eye without him having enough time to change it. This happens again when at one point he's wiping his eye and then suddenly his forehead. (00:07:45)
The One With The Halloween Party - S8-E6
Continuity mistake: The amount of carrot Chandler has keeps changing from less to more. (00:10:35)
The One With The Halloween Party - S8-E6
Continuity mistake: When Chandler and Ross are arguing, the nose on Chandler's costume moves. In one shot it's on his chin. The camera then cuts to Joey and Monica and back, and then it's down round his neck. (00:12:20)

The One With The Halloween Party - S8-E6
Continuity mistake: While Phoebe is calling out Ursula for lying to Eric, her hair continuously changes position from behind her shoulder to in front of her shoulder depending on the camera angle. (00:14:50)
The One With The Halloween Party - S8-E6
Continuity mistake: When Rachel returns from running after the boy that she told to "shut up", you see Joey picking up a piece of food, sniffing it and making a face and then putting it back on the tray. However in the next shot, without moving, Joey is munching on something - he didn't have anything in his hand before. (00:19:55)

The One With The Stain - S8-E7
Continuity mistake: After Gunther responds to Ross with the biting "ezels" retort, it cuts to Monica and Brenda in the living room, and when Monica falls off her chair, the rug and blue pad underneath are suddenly rolled up at the corner, then the rug is properly flat. (00:11:15)
The One With The Stain - S8-E7
Continuity mistake: When Monica asks Brenda to clean the top of the cabinets so that she can get a look at her crotch, Brenda drags a chair over (with both hands) to stand on. In the next shot, she is magically holding a feather duster. (00:11:40)
The One With The Stripper - S8-E8
Continuity mistake: When Phoebe is trying to place the stripper at the beginning, her coffee cup on the table keeps changing position. (00:00:50)
The One With The Stripper - S8-E8
Continuity mistake: In this scene in Central Perk, Monica tells Chandler she has hired a stripper for him as she feels bad for not letting him have a bachelor party, and tells him to think of it as a 2 month anniversary present. However this episode is set 2 episodes after the Halloween episode, therefore allowing us to assume it is set sometime in November or later. Chandler and Monica got married in May, as stated several times in the show by the cast, therefore they have been married for around 6 months or more, not 2 months. (00:07:00)
The One With The Stripper - S8-E8
Continuity mistake: When the stripper has just entered the apartment you can see her putting down her right arm twice, without enough time in between to put it back up. (00:09:50)
The One With The Stripper - S8-E8
Continuity mistake: When Ross and Mona are having their "make-up" kiss, Mona puts her left arm around Ross's neck, then in the next shot she does it again. (00:18:50)
The One With The Stripper - S8-E8
Continuity mistake: At the end of this episode, before the credits, Monica is giving a striptease for Chandler. Notice how the crown on his head changes position. Look at the coloured circles on this crown. (00:19:10)
The One With The Stripper - S8-E8
Continuity mistake: When Mona is saying thanks to Ross for showing her his rock collection she puts her hair behind her ear, then when she's leaving she puts it behind again.
The One With The Rumor - S8-E9
Continuity mistake: After Will has arrived and Chandler says, "I'm watching the game but I'm not deaf," you can see Will in the background with his hands on his hips. When the camera switches to just Will and Monica, Will suddenly has two wine glasses in his hands. (00:06:20)
The One With The Rumor - S8-E9
Continuity mistake: In the episode with Brad Pitt in it, when Ross and Will are standing by the fridge and Rachel comes in, Will's right hand jumps around after he crushes the decoration on the wall. (00:08:40)
The One With The Rumor - S8-E9
Continuity mistake: When Rachel is offering Will the yams, the spoon that's in the dish is facing Rachel. When the shot changes to Joey lifting up the Turkey, the spoon is suddenly on the other side of the dish and facing towards Will. (00:11:05)
The One With The Rumor - S8-E9
Continuity mistake: When Will is demanding yams, it shows Ross looking towards the door; the camera then cuts to Will, and Ross is now looking at Will without time to move his head. (00:11:55)

The One With The Rumor - S8-E9
Continuity mistake: When Ross hands Rachel the Yams in order to break the tension, the amount of food on both Ross' and Will's plates changes between shots. Also several wine glasses appear on the table. (00:12:30)

The One With The Rumor - S8-E9
Continuity mistake: The gang confronts Ross over his affair with a fifty-year old librarian when he was younger. If you watch the mirror behind him (in one of the girls' rooms), it changes angles every time the camera cuts between Ross and the rest of the gang. (00:17:40)
The One With The Rumor - S8-E9
Continuity mistake: Right near the end of the episode when Joey comes in wearing the maternity pants, he pulls out the chair from the table twice. (00:21:20)
Answer: The painting doesn't have a name, and if it does it is never mentioned in this episode.