Continuity mistake: Jack drops the two vials into the Tom Collins glass, while in the bathroom. At the hand-off, when he places the drink on the tray, there are no vials in the glass - there is no ice blocking them from view, just a skewer holding a maraschino cherry, a wedge of lemon, and a straw - no vials. Even Jack can't make the two vials invisible.
Continuity mistake: When Jack and Greg are in the motor home near the beginning of the movie, Jack is talking on the intercom mic to his family in the back, then puts it down when he is finished. But, in the following shot that shows Greg talking, you can see Jack's reflection on the window, showing him still talking into the mic.
Trivia: In the scene where the three men are in jail towards the end of the movie, the jailer that comes to let them out (but is stopped by Ben Stiller) actually plays a cop in the Comedy Central show "Reno 9-1-1". In fact, he may even be wearing the exact uniform he wears in the series. Also, the sheriff deputy who comes off the motorhome yelling "Look, he has rubber boobie!" is also a cop on Reno 9-1-1.
Trivia: The house used as the Focker's home (outside shots only) is the same home used in the TV show "Fantasy Island". The Queen Anne Cottage is located at the Los Angeles Arboretum, even though the movie is set in Florida. The outside of the house was re-dressed and so looks a little different.