Shoes, Hats, Pickle Jar Lids - S5-E9
Revealing mistake: When Charlie is in the Ferrari, his gets a call from Teddy. When Charlie brings the iPhone to his ear and talks to Teddy, you can see that the iPhone is upside down showing that no one actually called his phone.
Revealing mistake: Haley's pregnancy pad is visible when she raises her arms while lying on the table. (00:21:15)
Clash!! Sonic VS Knuckles - S1-E5
Revealing mistake: Right at the end of the episode, when Amy is telling Knuckles he should apologize, Amy has two right hands.
The Truth Is Out There - S1-E17
Revealing mistake: Gibbs finds a bunch of cash hidden in the victim's speaker. "For Motion Picture Use Only" is printed on them.
Revealing mistake: When Danny is driving Mr. Zhao in his convertible at night, you can really see that the background is a bad fake and since even though Danny is driving with the top down, his hair and clothing does not get ruffled at all by the wind.
Thrill Kill - S5-E1
Revealing mistake: When Dylan is being led out of jail, you can see palm trees in the background behind him. This reveals that the scene was filmed in Los Angeles, not Philadelphia.
Revealing mistake: When Billy lies dead in the morgue and the President fixes his hair while saying, "That's better." we can see Billy's throat move as he swallows.
Revealing mistake: In the scene in the kitchen, Lucille Bluth takes a bottle of "Bushmills" (a brand or Irish whiskey) out of a grocery bag during a scene in the episode; however the liquid inside is clear/transparent and obviously not whiskey.
Revealing mistake: During the dinner scene where Dave is thinking about Arsenio Hall eating cheese, Arsenio starts complaining about how good the cheese is. After punching one guy, he goes up to another and slaps him in the face. When he slaps him you can see he misses the guy's face by a good inch or so.
Revealing mistake: The phone message that Ryan leaves on Luke's voicemail is different to what he originally said, which is "I want to make sure you took care of it. Take care of it," but the message recorded is, "I'm just calling to make sure you took care of it. Take care of it." Also the background sounds from the club - the music, people talking, etc, are missing.
Revealing mistake: When Bubbles rips her wig off, her face is obviously paler than the top of her head, due to the fat-suit Matt Lucas was wearing.
Revealing mistake: After the Custos's house has been broken into, the next day, the Custos takes a key out of his jacket pocket, unlocks a drawer and takes out a pile of bound papers. When he closes the drawer, he doesn't take the key out of the lock, but he pantomimes his hand returning the key to his pocket.
Star Crossed - S1-E6
Revealing mistake: About twenty minutes into the episode, Tru sits down next to Jen. Jen says, "I saw you in line in the cafeteria." Tru, with her hands at her sides, says, "Tru." Jen says, "Jen," and raises her hand to shake, at which point Tru reciprocates. But how did Jen know that Tru was introducing herself? After all, pretty much nobody else is named Tru, so in context it would have sounded like Tru was saying, "True," as in, "True; you did see me in the cafeteria."
Revealing mistake: As Dr. McNamara is marking Megan O'Hara for her breast reconstruction surgery you can see the lower line of her prosthetic "removed breast" from her mastectomy on her left side. It is not the surgical scar from removing the breast, that is visible about an two inches higher closer to where the nipple should be. My aunt had a mastectomy, I know there should be no scar here.
Revealing mistake: In the episode with Fast Eddie McClintock, there are two revealing mistakes in the scene where Fast Eddie jumps the roadblock. First, the ramp he jumps off of is visible in numerous shots before he shows up. Second, explosive charges can be seen in the wheel wells of the police cars before they run over the spike strips.
Revealing mistake: Reapers look 'different' in reflections and recordings, yet sometimes you can catch them with 'normal' reflections, eg. Rube in the diner window.
Revealing mistake: In brother Justin's padded cell, the far wall is obviously a painted backdrop. It even flutters when the orderly and doctor walk in! The only solid part is a couple of feet at the end, that Justin leans up against.
Lightspeed - S5-E8
Revealing mistake: When the HIVE Five exit the museum and are intercepted by Kid Flash, Mammoth loses both his pants and the artifacts he has before KF whizzes past him. It's best seen in slow motion; at normal speed this mistake is hard to catch.
Revealing mistake: When Jamie sits down after rappelling down the canyon wall you can see that he has climbing rope attached to his harness. It's wrapped in duct tape to look like its the rope he and Adam made of duct tape. This may just be a safety line to support his weight if he duct tape rope snaps, but the Mythbusters usually point out any backup safety systems and explain that they are there for caution and don't contribute to the test. (This was explained in the aftershow. It was a safety line required by the shows insurers).