In trying to come up with a name for Santa's brother, Jessie Nelson, who came up with the idea for the film after her daughter asked her if Santa has a family, hit upon "Fred" while watching The Godfather (1972) on television. The name "Fred" is an homage to the character Fredo Corleone, the unreliable middle child of the Corleone family played famously in The Godfather (1972) and The Godfather Part II (1974) by John Cazale
Trevor Peacock, who was diagnosed with dementia in 2009, has no lines after the first scene where Nicholas is born. Peacock's longest line is, "Frederick, would you like to...come meet your brother?"
The wardrobe department consulted Levi Strauss and Company, and had special 501s created to accommodate Vince Vaughn's sizes exactly.
The extras in the People Help the People didn't even rehearse, causing natural reactions with Vince Vaughn.
Frank Stallone: As himself, and a member of the group "Siblings Anonymous". In the film, Stallone speaks about Rocky (1976) and First Blood (1982), two major blockbuster film series that star his brother, Sylvester Stallone.
Roger Clinton: As himself, and a member of "Siblings Anonymous". Clinton is the half-brother of former U.S. President Bill Clinton.
Stephen Baldwin: As himself, and a member of "Siblings Anonymous". The youngest Baldwin brother, he expresses his issues with the eldest and arguably most famous of his brothers, Alec Baldwin.
Jeffrey Dean Morgan: As the man to whom Rachel Weisz's character Wanda gives a parking ticket, and who then hits on Wanda.