The props department thought of putting the anklet on the cat cake at the last minute.
Due to many scenes being filmed at once, Matt's stunt double was used for scenes where you see Neal running down the street.
There was an earthquake in New York during the filming of the scenes on the tram.
The backdrop outside of Ellen's apartment - the river - is an actual view. It's not a fake.
During filming in the trams, both Tim DeKay and Matt Bomer were both on set - one just behind the camera in moments where there was only supposed to be one on the tram.