Honey, I Blew Up the Kid
In the opening scene of the 1992 movie Honey, I Blew Up the Kid, the youngest Szalinski child is watching Mister Rogers' Neighborhood as the family goes about their morning routine.

Notes
The clip seen in this movie comes from Neighborhood Episode 1633. Perfectly chose, the clip is from the end of the episode where Mister Rogers sings You're Growing.