Visible crew/equipment: After he gets beaten up by his father, Ricky looks in the mirror. On the left edge you can see a bit of the camera, then it moves away.
Revealing mistake: In the scene when Ricky's father rushes to his room and punches him, Ricky is bleeding before he is hit.
Continuity mistake: After Lester throws the pillow, it bounces off the couch and lands in the chair. In the next shot it's gone, but reappears in the following shot.
Continuity mistake: In the scene where Ricky's dad is driving him to school, if you look closely in the background, they drive by the same houses twice.
Continuity mistake: The interior layout of the Burnham's house does not match the exterior of the house. This is illustrated in the scene in which Jane comes inside after Ricky is taping her for the first time. She walks in the front door and goes directly into the dining room to peer out of one of the two side windows. If the interior of the house matched the exterior, she would not have been able to peer through those windows because they would not have existed. Instead, the garage would be there. (While there may be a window on that side of the dining room that does face out near the garage - extended external views of the house from that side are not plentiful in the film - there are still not two windows which face out in that direction. The garage would block one.)
Continuity mistake: When Lester is drinking from the blender in the kitchen, the amount changes the wrong way. First it's half full, then a third full, then half full again.
Continuity mistake: When Ricky comes home and starts to watch TV with his parents, on close up shots of the TV there are pictures and a vase on top of it, but when they show shots of Ricky and his parents, they mysteriously vanish.
Continuity mistake: When Lester is talking about the car he's just bought, the beer on the table has its label facing the camera. On the reverse shots, it's still facing the camera. The label doesn't wrap round - later on we see that there's one front label and nothing on the back.
Continuity mistake: When Caroline is cleaning the house she is trying to sell, she's in the kitchen cleaning the counter tops. The layout is her cleaning the breakfast bar counter and the sink is behind her to the left of her. When she takes a buyer through, the kitchen layout is exactly the opposite. If you look at the breakfast bar counter top, the sink is now on the right side. Also, you'll notice the "wall" to the left of the counter top now is pushed back a little - almost like they didn't align it correctly when they put it in for shooting.
Continuity mistake: When Lester is drinking from the blender in the kitchen, the bottles in front of the kitchen window are rearranged in between the shots.
Continuity mistake: During the night out at the estate agent's party, and back at the house that same night when drinking root beer in the kitchen, Kevin Spacey is wearing a t-shirt under his shirt. After hearing his daughter and friend talking about him working out he goes to the garage, finds his weights and takes his shirt off, but there is now nothing underneath.
Continuity mistake: When Lester is jogging towards Ricky and his father, you can see the hose on the ground. It first shows the hose stretched out across the lawn, then it shows the hose sort of coiled.
Continuity mistake: At the end, when Carolyn pulls over to the side of the road in the rain, the first shot shows her windshield wipers going, then in the close-up from outside, they are not, then from the inside of the van, they are going again.
Continuity mistake: When Lester returns from a jog after embarking on a fitness spree, it can be seen that the sweat pattern changes on his shirt in the scenes following the jog. They go from long and thick to long and thin to short and thick etc.
Continuity mistake: In the scene where Lester is telling Carolyn and Janie that he quit his job if you watch Carolyn's drink you see that it changes drastically from shot to shot, between having lots of ice, not that much ice, being quite full, not as full, etc. And she never even takes a sip.
Continuity mistake: When Lester is driving his Toyota after he quit his job, the plates on the car are different between the first shot (361813) and the second shot when he pulls in to the burger place (315502).
Continuity mistake: When Carolyn calls Lester and Jane out whilst honking the horn, the shot changes from her to the house several times. Each time the shot is facing the house the side mirror is flapped in and while facing her it isn't. Additionally, in the same scene when Lester comes out, his briefcase opens and his cellphone falls out toward the car out of reach, when he picks it up again it's right next to him.
Continuity mistake: In the kitchen near the end of the film when Angela asks Lester if he's been working out, there is no sweat on his arm in four successive medium shots. When she touches the arm in the close-up, it is glistening wet.
Continuity mistake: Lester decides to exercise his body after listening a conversation between his daughter and her friend Angela. He goes to the garage and looks for his instruments, dropping several things to the floor. We can see some of them, but a second later when he didn't even tried to pick them up, a big one has suddenly dissappeared and never comes back.
Continuity mistake: When Lester is in Janey's room and he is looking through her phone numbers, when he gets to Angela's number it starts with 555 but when he dials it on the phone the first two numbers are a similar beep but the 3rd is a different tone. It looks as if he is hitting 553.
Continuity mistake: In the first overhead shot of Lester in bed, just before his shower, his slippers are positioned in a V-shape, but in the next shot, from under the bed, has them parallel to the bed.
Continuity mistake: In the scene where Carolyn threatens to divorce Lester the bedclothes on the bed are halfway up, then down, then halfway up again.
Continuity mistake: In the scene where Col Fitts comes into Ricky's room to retrieve the urine sample the refrigerator is on the left of the door as is the bed. This is also how the room is set up when Jane is being filmed by Ricky in Ricky's room. However when Lester is in Ricky's room to buy marijuana from him for the first time the bed is on the opposite side of the room. The bed is also like this when Col Fitts is hiding in Ricky's room after Ricky delivers more marijuana to Lester later in the movie.
Continuity mistake: When they are eating at the dinner table you can see that there is no rug, but later when Jane was looking out the window after the first time she was being video taped you can see that there is a rug under the table.
Continuity mistake: Near the end of the film, Angela comments on Lester's shape. At this point, Lester is sitting on the counter with his arms stretched, supporting himself. But when Angela touches his arm, his elbow is bent.