Springfield Connection - S6-E23
Homer: When Marge joined the police academy, I thought it would be fun and exciting, you know, like that movie, "Spaceballs." Instead, it's been dark and depressing, like that movie "Police Academy."
Springfield Connection - S6-E23
[Hans Moleman is about to be executed and Homer has eaten his last meal.]
Reverend Lovejoy: Alright Hans, time to go.
Hans Moleman: But he ate my last meal.
Reverend Lovejoy: If that's the worst thing that happens to you today, consider yourself lucky.
Hans Moleman: Are you really allowed to execute people in a local jail?
Reverend Lovejoy: From this point on, no talking.
Answer: I'm not sure if this is the one you're thinking of, but an episode of "Ray Bradbury Theatre," called "A Sound of Thunder," dealt with a similar matter: a group of hunters travel back in time to hunt dinosaurs, only to find things have changed when they get back because someone stepped on a butterfly.
Xofer