Homer: If you really want something in this life you have to work for it. Now quiet, they're about to announce the lottery numbers.
Homer: Please press any key. Where's the any key?
Homer: What are you gonna do? Release the dogs? Or the bees? Or the dogs with bees in their mouth and when they bark, they shoot bees at you?
Homer: To alcohol - the cause of, and solution to, all of life's problems.
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