The curtains in the room where Pat sees the "old fashioned" lady have the same pattern as the carpet in The Overlook Hotel in The Shining (1980).
This episode contains four actors who also appeared on Friends (1994). Courteney Cox played Monica, one of the main characters, while the others all appeared as supporting cast in different episodes: Greg Kinnear (The One with Ross' Grant (2003)), Merrin Dungey (The One Where Chandler Takes a Bath (2002)), and Sherilyn Fenn (The One with Phoebe's Ex-Partner (1997)).