Cape Feare - S5-E2
Trivia: Bob's prison number is A113. This number is often used as by alumni of California Institute of the Arts (most famously by Brad Bird, in his Pixar films and episodes of the Simpsons he was involved in, such as this one) - it's the number of one of the classrooms.
Cape Feare - S5-E2
Trivia: The gag of Sideshow Bob stepping on the rakes was only supposed to be him stepping on a single rake one time. But the episode's running time was short, so the sequence was extended as a time filler.
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