Visible crew/equipment: When Kel gets up to get more water you can see one of the cameras.
Freeze Frame / Phoebe Cheats - S2-E8
Continuity mistake: The next night, Phoebe's bed clothes switch back and forth between her nightgown and her dress.
What Does Blue Want to Make? - S1-E15
Visible crew/equipment: A boom mic is visible when Steve starts singing "We Just Got A Letter."
First Kiss - S1-E17
Visible crew/equipment: At the end of the episode when Harvey hops away, a boom mic is visible. (00:21:55)