Rachel gets a tattoo on her hip in this episode and it is never mentioned again.
Jack says: "It looks like a scene from Cocoon", Courteney Cox appeared in Cocoon: The Return (1988), the sequel of Cocoon (1985).
The first episode with Joey's name in the title.
When Judy says Richard has got himself a Twinkie in the city this is likely a reference to to the 1970 film Twinkie (Lola) about a 38 yr old novelist Charles Bronson who runs off and marries and sets up home with a 16 year old schoolgirl Susan George
At Jack's birthday party he has a signed Harmon Killebrew baseball bat. Killebrew played for the Minnesota Twins who are at times called "The Twinkes" the same nickname unknowingly given to Monica for dating the much older Richard.