The apartment that Ira, Leo, and Mark live in are the Larchmont Lofts on the corner of Melrose Ave., and N. Larchmont Blvd., in Hollywood, California.
Judd Apatow: (family) Leslie Mann plays mother to her real-life daughters with Apatow: Maude Apatow and Iris Apatow, just as she did in Knocked Up (2007).
When Ira is playing the mix he made for George, George objects to the first song because Bob Marley died of cancer, which reminds George of his own medical condition. Actually, all three of the songs that Ira plays have a strong connection to a famous man who died of cancer: in addition to the Bob Marley song, he plays "(I've Had) The Time of My Life", which is most famous for its prominent inclusion in the movie Dirty Dancing (1987) (that movie's star, Patrick Swayze, was undergoing treatment for pancreatic cancer while this movie was being filmed, and he died in September 2009), and next, he plays "Keep Me In Your Heart" by Warren Zevon, who died of lung cancer in 2003.
Eric Bana's character is, like Bana himself, a St Kilda supporter, which is a team in the Australian Football League (AFL). Bana attended the 2009 AFL Grand Final in which St Kilda was playing. (They unfortunately lost by 12 points to Geelong.) In 2010, St Kilda again made the Grand Final, this time against Collingwood - the very same opponents that Bana's character despises. A rare replay was scheduled for Saturday 2 October 2010 after the first Grand Final ended in a draw at 68 points each.
Adam Sandler said, in interviews shown in the credits of Australian pay TV viewings, that casting Eric Bana made the fight sequence more realistic, especially because the Australian would be seen as the stronger combatant.
The film features Warren Zevon songs "Keep Me in Your Heart" and "Numb as a Statue" from the 2003 Album "The Wind". Zevon began recording the album shortly after he was diagnosed with inoperable lung cancer and it was released just two weeks before his death.
Adam Sandler turned down the role of Donny in Inglourious Basterds (2009) to play George Simmons in Funny People (2009). Eli Roth took over the Donny role.
Though billed prominently as a star of Funny People (2009), Eric Bana appears only in the last third of the film.
When George Simmons goes to talk to Ira Wright at the deli, Ira is standing behind of a dark red menu. When he walks away you clearly see that one of the dishes listed is "Chopped Liver".
Judd Apatow: (Raymond) Everybody Loves Raymond (1996) is mentioned in The 40-Year-Old Virgin (2005), Knocked Up (2007), and Funny People (2009). Ray Romano appears as himself and the object of Eminem's disdain in "Funny People."
Leslie Mann plays mother to her real-life daughters (with director Judd Apatow) Maude Apatow and Iris Apatow, just as she did in Knocked Up (2007).
In Knocked Up (2007), there is a scene where the guys are sitting around talking about that, if they "got laid", it was because of Eric Bana in Munich (2005). Bana also stars in this film, and coincidentally (or perhaps not) the director of photography on both Munich (2005) and this film is Janusz Kaminski. Barry Mendel, one of the producers of Munich (2005), is also a producer on this film as well.
The characters of George and Ira were written specifically for Adam Sandler and Seth Rogen.
George (Simmons) and Ira (Wright) are named after the composer/lyricist brothers George Gershwin and Ira Gershwin.
Judd Apatow considered Bill Hader for the role of Mark but decided to give it to Jason Schwartzman instead.
Judd Apatow and Adam Sandler were old roommates. The footage seen in the opening sequence was recorded back then. Sandler would regularly make prank phone calls and one day Apatow decided to start filming them.
The plot of the film and its characters are loosely based on F. Scott Fitzgerald's novel The Great Gatsby.
Adam Sandler said he felt guilty about saying such filthy jokes in the film about women because of his two young daughters at home.
Aziz Ansari's character, Randy, proved to be so popular on the set with the cast and crew that Judd Apatow shot a Randy "documentary" and is developing a Randy feature film. Ansari also incorporated Randy into his regular stand-up act. Ansari has said that he based Randy on Soulja Boy. He imagined what if Soulja Boy was a stand-up comedian and wrote jokes based on that idea.
All featured footage of a younger George Simmons is real footage of a younger Adam Sandler, although all of the movies of George Simmons are fake.
The cameo by 'James Taylor' at (I) the MySpace show at which George and Ira performs was originally intended for Bruce Springsteen.
At one point in the movie George Simmons goes to talk to Ira Wright at the deli, Ira is standing behind of a dark red menu, when he walks away you clearly see that one of the dishes listed is "Chopped Liver".
A poster for The Last Detail (1973) can be seen in Ira's apartment, which is one of Seth Rogen's favorite movies.
The opening video with the prank calls is a real video shot by Judd Apatow when he and Adam Sandler were younger. The two other people appearing in this video are Janeane Garofalo and Ben Stiller.