The scene where Lulu tells Shane that she thinks he's cute and Shane's embarrassed response was based on a real-life incident on set. Morgan York (the actress who plays Lulu), upon meeting Vin Diesel, actually said that to him and he awkwardly responded with a "thank you". The director thought it was so funny that he put it in the film.
Originally, Jackie Chan was attached to this film. The ninjas in the movie are from his stunt team. Ironically, Jackie Chan would later appear in The Spy Next Door (2010) which has a similar premise to this film.
Boo Berries cereal is not sold in Canada. Adam Shankman's assistant had to drive to Buffalo, New York to get it.
The idea of the family having a pet duck was introduced by Thomas Lennon and Robert Ben Garant when their script had Jackie Chan attached. The running joke was that Chan's plan to kill the duck and cook it for dinner horrified the kids, and therefore Chan ended up reluctantly keeping and taking care of the pet. Even when Chan exited the project and other writers worked on the script, the duck stayed all the way through to the finished film.