Revealing mistake: As the gang drives up to the space-ship diner, cars are whizzing by in the background. When they are driving to the base there's also a clip of a fire truck going down the highway in the distance.
Broken Link - S4-E26
Revealing mistake: During the fight between Garak and Worf near the end of the episode, a Jefferies tube door is knocked out of its frame to reveal the end of the set - a dark room with a wooden scaffold and various other pieces of equipment (slow-mo helpful but not required). (00:36:00)
The Magician - S3-E4
Revealing mistake: When Oliver meets Thea at the Grind and Jot Cafe (Which looks unsurprisingly like CC Jitters) you can see the cups on the table are from CC Jitters. (00:20:50)
Encounter at Farpoint (1) - S1-E1
Revealing mistake: When Q freezes Torres on the bridge, it is easy to tell that directional hoses were used for the effect. (00:06:25)
Revealing mistake: (Ep. 4) After Omega takes off his mask and looks in the mirror, when he sees that his physical body doesn't exist he puts his mask back on and screams, but when he shouts, "If I exist only by my will, then my will is to destroy," Omega's mask pops up off his face, and we can see the actor's blackened face as he shouts the last bit of his dialogue. (00:07:10)
Revealing mistake: After Rygel realizes that he can loosen the soil with the dumped gruel, it cuts to John and Aeryn as they approach the Tavlek camp, and when Aeryn tells John, "I am going to take out every last Tavlek. No survivors. No mercy. Now give me the oculars," John holds up the syringe (with Zhaan's sleep mist) that Aeryn had given him earlier, and we can see "DG-4" engraved on the side of the gun, revealing that the prop dept used the model DG-4 aluminum air blow dust gun to play the part of the syringe.
The Night of the Bubbling Death - S3-E1
Revealing mistake: As West drags the body of a bad guy out of the scene, the supposedly unconscious man is holding his head up so as not to have his head dragged through the dirt. A truly unconscious person's head would flop back on to the ground.
The Bridge - S1-E10
Revealing mistake: Agent Coulson turns the steering wheel several times despite the car being on a straight street.
Revealing mistake: When Brad wears the sunglasses and holds the pole, you can easily see the string that holding it up.
Knight Rider [Pilot; a.k.a. Knight of the Phoenix] (1) - S1-E1
Revealing mistake: When KITT takes part in the race and goes up on two wheels, you can see that the stunt driver is behind the wheel and that a dummy is strapped into the passenger's seat.
Confidence and Paranoia - S1-E5
Revealing mistake: After Lister faints, you can see him smirk when the cat sings 'S-E-X, I think I've found it!' (00:08:50)
Revelations - S5-E22
Revealing mistake: Just before Teal'c and O'Neill get to the engine room door, Carter can be seen hiding around the corner. (00:27:40)
Revealing mistake: When the dummy plane is shot out of the sky by the fighter pilot, a piece of the plane shoots off into the top left of the screen and bounces off the sky background. (00:23:05)
The Return of Wonder Woman - S2-E1
Revealing mistake: During the scenes on the jet with Steve and the others, before landing on Paradise Island and when the Amazon women are aboard, the end of the cabin and cockpit sets are visible at either the right or left side of the screen in some shots (widescreen version).
Children of Earth: Day One - S3-E1
Revealing mistake: When the children are possessed by the 456, they're supposed to be frozen and stare blankly ahead. But during the second possession, as the camera is panning across a school playground, a boy on the far right is looking directly at it. As it moves closer to him, he swivels his eyes back to where they're supposed to be. (00:16:30)
Revealing mistake: The stick of dynamite Brisco throws lands to the right of where the pyrotechnic for the dynamite explodes.
Revealing mistake: The solid brick wall bends like vinyl when Colonel Malloy touches it.
Logan's Run - S1-E1
Revealing mistake: Logan and Jessica commandeer a hover car that floats above the ground, but in shots of the car moving, wheels of the prop hover car are seen.
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.