Punk Chick - S1-E22
Revealing mistake: While cuddling in the car Donna tells her boyfriend that she isn't wearing a bra when it is obvious that she is - at one stage when she leans toward him her sweater tightens across her back and the shoulder strap and clasp of her bra is outlined.
Roller Disco - S3-E5
Revealing mistake: When Jackie and Fez are doing their Roller Disco routine, it becomes very obvious that doubles are used for many of the routines. Fez does a lot of his own stunts but Jackie does very few. While they do a decent job of hiding the stunt doubles, there are several times when you can see the faces of the doubles and it is obvious it is not Mila Kunis or Wilmer Valderrama. And you do not need slow motion or stop action to see the difference. (00:11:10)
Revealing mistake: Hyde claims he's reading a Mad Magazine spoof of Smokey and The Bandit. Look closely at the issue, and he's actually reading a spoof of the movie Dog Day Afternoon. That and Mad Magazine didn't make any parody of Smokey and The Bandit.
Eric's Drunken Tattoo - S3-E22
Revealing mistake: In the scene where Eric tries to kick Donna's door open. When he does, he falls back and hits the wall behind him, which wobbles.
Revealing mistake: The scene where Donna and Eric are running towards each other, each shot of Donna and Eric individually shows them running past the same umbrella and surfboard. They were using the same section of the beach to shoot both Eric and Donna running.
Revealing mistake: When Fez and Suzy first meet, they do "12345 you owe me a coke" you can see Kelso mouthing the same line as well. (00:08:04)
Chosen answer: Danny Masterson is the one who screams "hello Wisconsin".