Mr. Monk and the Astronaut - S4-E14
Plot hole: There is no drug in the world that could render a healthy adult unconscious for two days with a single dose, but let's go with the dramatic licence and allow that there is. Any such drug would be instantly detectable in any one of a dozen toxin screens carried out during an autopsy, and isn't someone going to wonder how a comatose woman hanged herself?
Plot hole: At The Beginning Sam stated that the missing teacher comes to work by subway every day. But in the flashback of his conversation with the drug dealer, he's about to get into his car. (00:13:00)
Plot hole: In the very last episode of the show, "George Decides To Sta-Local Where It's Familiar", Angie mentions that they conceived their "kids" there, referring to both Carmen and Max. However, the season four episode "George Takes a Stroll Down Memory Pain" showed flashbacks where Angie and George were living with Benny, and Angie was far along in her pregnancy with Carmen. Only Max could have been conceived in the house that they are currently living in. I want to add that in the episode 'Valentine Massacre', George says"What about the first time we made love. What were the odds in Vegas!?!"
High Octane - S5-E7
Plot hole: When Dex is doing the jack in the box ,he is hanging out the sun roof driving with his feet, using the cruise control. When he is decapitated, the body falls and the car spins out and stops. The car's cruise control was still on. The car should have kept going until the brake was pressed. Even if the body hit the brake on the way down, it would have coasted to a stop and not spun out and screeched to a stop.
Here There Be Monsters - S1-E10
Plot hole: The female police officer has a theory that Johnny was the Strangler in the case the papers claimed he helped solve but this hardly makes sense. If she was researching him as was seen in the episode, surely it would have said something about Johnny being in a coma during the bulk of the murders since the story was about Johnny.
Plot hole: When Kel is giving a toast to Kath at the restaurant, he says that he has been married to Kath for a month. In Episode 8, Series 1 "The Wedding", their wedding was held on 18th September yet it is New Year's Eve now. That's not a month, that's at least three.
Forever Red - S1-E34
Plot hole: Tommy states that he and the other Zeo Rangers destroyed the Machine Empire's leaders and ultimately destroyed the Machine Empire except for the Generals who escaped. This is not true - Lord Zedd and Rita destroyed the Machine Empire leaders at the end of series 4, and the Space Rangers destroyed them again in Countdown to Destruction in series 6. The Zeo Rangers never destroyed the Machine Empire.
Suggested correction: How would Tommy know that? He didn't watch the show or know the ins and outs of what happened in space. This is what he believed based on his experiences on Earth. Everything you described is factually correct, but Tommy did not witness this. So, to his knowledge, he destroyed the Machine Empire.
Plot hole: In Cam's song in the dream, one of the lines is: "No fun, no sun." However, at the start of the dream, all of the Dumping Ground kids are outside in the daylight.
Normal Boy/Birth of a Salesman - S1-E3
Plot hole: Throughout the show, many characters state that Jimmy was responsible for the meteor almost destroying Retroville in the episode "Normal Boy", however, how would anyone even know that? The meteor was put on course after being hit by some kitchen objects shot into space by Jimmy's orange juice machine. Neither Jimmy nor his parents or anyone saw the objects go into space, much less witness them causing the meteor head straight to earth, especially since the meteor wasn't detected until the next day.
A Scooby-Doo Valentine - S3-E3
Plot hole: It's never explained how JC Chasez and the Hollywood extras impersonating the gang gained the super strength they possessed to do things like ripping car roofs open or holding up the Mystery Machine.
Episode #5.2 - S5-E2
Plot hole: Collision between the two planes would have been prevented by TCAS (traffic collision avoidance system) computer systems installed on both planes. The TCAS systems automatically coordinate with each other and issue a TA (Traffic Advisory) with an audible "TRAFFIC, TRAFFIC", then if on a course that could result in a collision or near miss, issue an RA (Resolution Advisory) to their respective flight crews. Typically one plane's flight crew is audibly ordered to "DESCEND, DESCEND" by its' TCAS and the other plane will be instructed to "CLIMB, CLIMB" by its' TCAS. The flight crew is required to follow their TCAS instructions over the air traffic controller's. All commercial airliners are required to have a functioning TCAS computer. These systems were obviously not under control of the terrorists, they were conveniently ignored in the plot. (00:03:20 - 00:06:47)