Goofs

When Robert and Nancy say "No television for a week" Brennan throws his ice pack down in one view and Nancy says, "We are so serious," Brennan throws the ice pack down again.

In the car during the "Sweet Child O'Mine" scene Tommy is shown playing a PSP (Playstation Portable) he is also holding a stylus. The PSP does not have a touch screen.

Brennan rubs his testicles on the drum set. When Dale knocks him to the floor, Brennan's testicles are still out. When he is fighting Brennan, his pants are zipped up.

Brennan is in Randy's office asking to be given the task of the Catalina Wine Mixer. Derek comes in and says to Randy, "Did you tell him the deal?", obviously making it clear he already knew that Brennan was given the job. However, after hearing Brennan out, Derek then decides to give Brennan the job. (In the DVD extras, this goof is explained because an alternate take (entitled "Catalina Heart Attack") shows Randy giving the job to Brennan without Brennan needing to ask for it, or repeat his request to Derek. Then Derek comes in and says the same line.)

At the start of the job interview, a lady tells Brennan Mr Jeener will interview him, but in the next shot Brennan is interviewed by a lady called Pam.

When Derek gets his golf club at the Prestige Worldwide premier, he say's he got a Callaway 3-wood, but in reality, he got a driver, which is a much larger golf club.

In the treehouse, Derek tells Brennan and Dale that he "hasn't had a carb since 2004." In the dinner scene just before that, he drank a Heineken. Beer is mostly carbohydrates. This was most likely done on purpose as Derek likes to brag and make up stories, he was probably exaggerating his diet.

When Derek comes over for Christmas dinner, he mentions that he was driving around with his buddy in a "brand-new" Testarossa. Ferrari stopped production of their Testarossa sports car in 1996, so Derek could not possibly be driving a brand new one. But, since Derek takes such pride in his accomplishments and the people he knows, it's possible that by the time he was 24 years old (his age in 1996) he could already be established enough to know someone with a brand new Testarossa. Derek never states what year this particular story takes place.

During the school yard fight at the end, the "students" are clearly much older stunt doubles.

Despite Dale's top bunk falling on top of Brennan he only suffers a minor cut.

When Brennan is trying to scare off potential buyers of his family's house, the swastika on his Nazi SS uniform is backwards.

Brennan is 3 years older than Derek. But in the flashback at the end, with the 2 brothers flying the kite, they appear to be the same size and around the same age.

In the flashback scene (Brennan has a mangina) everyone looks the same as they do in 2008 except for Nancy who actually looks younger.

In the car during the "Sweet Child O'Mine" scene Tommy can be seen switching from sitting in the middle of the back seat and then to the far right and then back again in the middle between shots.

In the beginning, Brennan is 39. Later, during a bedroom scene with Dale and Nancy, it's revealed that Brennan was 17 when his brother, Derek, won a talent show by lip-synching "Ice Ice Baby." If the movie takes place in 2008, then the talent show was in 1986. "Ice Ice Baby" was released in 1990.

During Brennan's song at the Catalina Wine Festival, the drums don't match up with what Dale is playing several times.

At the Wine Mixer, Dale plays drum rolls with yarn mallets, but it sounds like he's using drum sticks. Performing a drum roll with mallets would sound very different, and be a lot more difficult.

As Derek and his family sing "Sweet Child of Mine," Derek's audio track is clearly off as Tommy sings his solo, especially in the shot of Derek and Alice as the camera pans back to Tommy.

After the drive home following the Prestige Worldwide presentation, the boys burst into the house. A crew member in black clothing, trying to stay out of the shot, is reflected in a mirror beside the main entry door.

When Robert and Nancy are in the bedroom after he gets back from the Cheesecake Factory, a crew member's shadow is cast across Robert just as he is about to sit down.

When the two brothers are on the boat, the reflection of the camera in the polished metal arm under the wheel of the boat is visible.

When Brennan and Nancy move in with the Dobacks, Dale and Brennan introduce themselves to each other on the front lawn. Somehow, their parents fell in love and got married and their sons never met before moving into the same house.

At the Catalina Wine Mixer, Dale plays Boats n' Hoes. While he is on stage, Brennan is still talking to Robert. In one shot though, Brennan is talking to Robert, and no one is at the drum set, but Boats n' Hoes is still playing and Dale is still singing.

When Brennan is up on the stairs swearing, his mom calls him Brandon.

When Dale is showing Brennan the house he says the house was built by General Custer in 1825. Custer was born in 1839.