Earlier this year in class, we watched a few minutes of a film titled, "Run Lola Run". I found this film interesting because it made use of a concept I was only otherwise familiar with through a small short story from my favorite Science Fiction writer, A Sound Of Thunder, by Ray Bradbury. Bradbury's story describes a safari company which allows it's hunters to travel back in time to hunt prehistoric prey. The film's protagonist, disobeys the protocol, and ultimately kills a small butterfly during the period of the dinosaurs. Returning back to the future, he discovers he has made a subtle but significant change in the state of nature: A different man is President of the United States, letters are slightly different, among several other small changes.
This "butterfly effect" was interestingly illustrated in "Run Lola Run", in which through a series of flashbacks and flash forwards, we see that through small changes in the primary events, the later chain is sparked along a slightly different chain. I found this interesting, primarily because of it's relationship with free will, and our lives altogether.