As Chandler is leaving for Tulsa, he tells Monica to have Geoffrey (who Monica claimed was the funniest person she ever met) email him with funny Oklahoma jokes at www.hahanotsomuch.com. This was a real web page with various quotes from that episode which has since been removed.
The 200th episode of the series.
The Busty Ladies magazine Joey reads is the same one picked up by Ross in the beginning of the episode "The One that Could Have Been: Part 1" (2000).
Sandy was originally set to played by Tom Hanks, but he was shooting a movie and had to drop out due to scheduling conflicts. Freddie Prinze Jr. was cast the day before filming.
Lisa Kudrow's husband was on set the day they filmed the scene where Phoebe places Mike's hand on her breast.