The One With Monica and Chandler's Wedding, Part 2 - S7-E24
Continuity mistake: The way Phoebe holds her flowers when told to smile changes depending on the angle. (00:04:30)
The One With Monica and Chandler's Wedding, Part 2 - S7-E24
Continuity mistake: As Chandler meets Monica at the altar, Monica's hand switches from holding Chandler's hand, to holding the flowers, with no time to do so. (00:40:40)
The One With Monica and Chandler's Wedding, Part 2 - S7-E24
Continuity mistake: During an earlier episode Monica gave up her dream wedding dress so Chandler could have The Swing Kings at their wedding. So it is a little surprising that the band they actually have are called Jungle Swing.
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.