It was based off a novel by one of the more Popular scifi guys. It dealt with a team who would take people on Time travel Safaris, But they had to stay on this Electric sidewalk thingie. I guess the movie comes about how one man stumples off the safty area, Just for a second, and all of time is changed. It just came out this year IIRC, But for the life of me, I can't think of the name of It.
Stephen