The One With Joey's Big Break - S5-E22
Factual error: Joey and Chandler are supposedly crossing the George Washington Bridge but the exterior background viewed from inside the car is very obviously a repeat reel of another bridge, and their conversation goes on for far too long for the actual crossing. And the cutaway shot after Chandler is kicked out of the car shows an aerial view of the Brooklyn Bridge.
The One With Joey's Big Break - S5-E22
Factual error: In the scene where Joey is supposedly in the Nevada desert, Saquaro cacti are seen in the background indicating that the scene was shot in Arizona or Mexico.
Answer: Usually by the seventh night of Hanukkah you don't know what to get the other person, and you will probably resort to getting the other person something insignificant. Chandler is basically saying that the pen is a stupid gift.