The scene where Ross gives the lamp to Chandler wasn't scripted. David Schwimmer unintentionally handed it to Matthew Perry. Perry's reaction fitted perfectly with the scene.
Helen Baxendale (Emily) became pregnant between seasons 4 and 5 and was unable to travel to the US to do any filming for season 5. As a result her only appearances were heavily swaddled in bed clothes, and she had to be written out of the series a lot earlier than intended.
The uncut DVD version of the episode features an additional scene where unsuccessfully Ross tries to convince Carol and Susan to move to London.
The Magna-Doodle reads "Evil Joe."
In this episode, Rachel states that Monica mentioned her "secret boyfriend" (Chandler) was the best sex she has ever had, which is ironic because Monica is the one who explained/taught the 7 erogenous zones earlier in the series to Chandler when he was dating Kathy.