The One In Vegas, Part 2 - S5-E24
Factual error: When Monica rolls an 8 to buy everyone a steak dinner, the one die is positioned with a 5 and 4 facing the camera (the 5 on the left, and 4 on the right). With the die that way round a 1 is always on top. There is no other way to get the 5 and 4 combo. This means that Monica had a 7 on the other die, That is impossible. And so she did not roll an 8. (00:31:35)
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.