Continuity mistake: In the old man scene, the house that lands on Knoxville goes up with nothing on the side of it, then when it lands on him, it has the jackass symbol on the same side.
Continuity mistake: In the opening credits, the guys are standing full depth in the giant shopping cart. When they get to the bottom, the cart most noticeably has a platform halfway down that the guys are standing on when they get thrown out. [It is mentioned on the cast commentary (by Bam) that they needed to raise it up because they were afraid of jumping out from so low down in the trolley. Still a mistake, but that's why it's there.]
Other mistake: In the Rube Goldberg Test scene, read the subtitles when Rip Taylor is talking. In the actual movie (where all we see is Johnny Knoxville coming out of the catapult) the subtitles have him saying "Oh, child." at one point. In the extras (where we see the complete Rube Goldberg Test), the subtitles show Rip saying "Oh, John." for the same line.
Revealing mistake: In the scene in which Ryan Dunn jumps into cacti with his BMX bike Preston Lacy is supposedly yanked off of his couch by the momentum of Ryan's jump. However, if you look closely in the background it is obvious that Preston Lacy hardly moves at all from Ryan's jump and the effect was edited in later. [In reality, Dunn barely even movied Lacy. The crew reshot it and pulled Preston off the couch by hand.]
Continuity mistake: In the opening shopping cart scene with the cast, you can see on a wide shot that Wee Man is in between Johnny Knoxville and Bam Margera, but in the next scene when Bam hits Dunn you can see Wee Man is sitting in the front of the cart in the seat, in the next wide shot Wee Man is back in between Knoxville and Bam again.
Visible crew/equipment: In the old man scene at the end of the movie after the credits roll, Ryan Dunn was supposedly launched into the air by an explosion. If you look closely after he hits the building you can see the cable that is lifting and holding him up.
Continuity mistake: In the scene where Ehren makes the yellow snowcone there is a editing mistake. In one shot, his snowcone is almost gone. In the next shot, his snowcone is barely eaten.
Continuity mistake: When Ehren McGhehey is eating his yellow snowcone and is holding it above his head so he can catch the drops, which are dripping from the bottom of the cone, there is a good amount of snow left in the snowcone, but in the previous shot there was almost no snow left.
Revealing mistake: Now it is said by Dunn that at the end, when Dunn craps out the toy car, it is shown again in the credits, but is put in reverse so the shot looks like it was filmed at a different angle.