Towards the end of the episode, Joey and Chandler are grabbing Phoebe from either side. Their positions alternate between shots.
The accent of Margha is clearly not Dutch. (It's more a kind of Russian accent)
The NFL game on TV is between the New York Giants and the Minnesota Vikings. These two teams have never played against each other on Thanksgiving. The only home teams for Thanksgiving Day Games between 1970 and 2005 have been the Detroit Lions (every year), the Dallas Cowboys (every year except 1975 and 1977), and the St. Louis Cardinals (1975 & 1977).
Chandler doesn't like football but in this episode he is seen watching and playing it. (In The One With Chandler In A Box episode, Chandler pretends to want to watch "the big game" and Phoebe says "You don't have to do that, Ross and Joey aren't here, you can watch the parade if you want." to which Chandler replies "Thanks.").
Correction: In this episode, Chandler watches football together with Joey and Ross. It is possible that he's only doing it to fit in with the guys (and as correctly mentioned above, it is revealed later in the series,that he doesn't actually enjoy football). He is also pressured into playing, and sort of guilt tripped into agreeing to play. It might be because he wasn't in the mood due to his break up with Janice, but it might also be because he doesn't like playing football either.
When Chandler makes a touchdown he runs right into the set and bits of what are supposed to be a cement wall and wire fence jiggle and then go back into position.
For the kick off, it's obvious Ross extended his right ankle so Chandler can "accidentally" kick it.
Monica says that the last Geller Bowl was 6... however on the Geller Cup, you can see years ranging from '77-83, 7 years. Which would mean it would have been Geller Bowl 8 that they played, but no one won... in 1984.
After Monica says the line "to score the winning touchdown by the way",
She is seen mouthing "by the way" again when Ross begins his next line.
When they are playing football in the park the boom mic is briefly visible.
Ross tells Chandler to run a post pattern on one play. A post pattern in football is a pattern where the receiver runs forward, then diagonally towards the center of the opposing end zone (towards the goal post, or in this case the imaginary goal post). Chandler runs a reverse on that play, not a post.