Most will be able to identify with this genre through movies like Groundhog Day. Basically, the premise is based on characters who are trapped in a rip or anomaly in time and/or space that causes them to repeat it. Different movies will put different spins on this - time machines, Bermuda Triangle, lightning, you name it - but either way it takes great writing to really pull this off. Of course a healthy suspension of disbelief, some imagination and at least a slight interest in science helps.
10. The Butterfly Effect (2004)
Ok, so I dislike Ashton Kutcher as much as the next guy... what... the next guy loves Ashton... man, people are weird. Anywho, in spite of Kutcher starring in this movie it's actually pretty good. He plays a young man who suffers from blackouts and keeps a diary to remember as much as he can. After examining his past diary entries he is able to have remarkably vivid flashbacks in which he is actually able to alter his future by changing the details from his past. Although I don't really care for the actors in this, the writing and directing prevail to create a pretty entertaining movie.
9. Groundhog Day (1993)
8. Bill and Ted's Excellent Adventure (1989)
Maybe a weaker example of the time loop, this is certainly fun enough to include in this list. A couple of burnouts realize that they must save the world with their rock music, but must first go back in time to learn about all kinds of historical dudes and stuff so they can present a killer history presentation to continue with their fated futures. The loop comes into play during certain scenes when they interact or see their "past" selves. A bit dated, but certainly worth the watch if you can handle the corny humor and air-headed slang.
7. 12 Monkeys (1995)
6. Source Code (2011)
Ok, so this one may technically be an alternate universe rather than a time loop, but hell... it still counts. Jake Gyllenhaal stars as a soldier who wakes up to find he's in the body of another man on a commuter train. While regaining his bearings the train suddenly explodes and he wakes up again in a metal pod where a woman on a TV screen informs him that he is part of a military experiment. He is being sent back to a certain time and place earlier that day to identify the train bomber before he can strike again. So over and over he returns to the same situation and tries all sorts of methods to reach his objective.
5. Donnie Darko (2011)
Cult director Richard Kelly just gets the imagination of sci-fi as he's proven with most of his movies. Donnie Darko may be one of the best examples. Jake Gyllenhaal (in the earliest of his two time loop movie appearances) stars as a troubled teenager who serendipitously avoids his own death as a plane engine falls through is bedroom while he is not there. Afterwards, he begins to have visions of a creepy rabbit-man that manipulates him into committing a series of crimes. Now seeing what his life has become after the bizarre incident he is sent back to that very night to decide for himself whether to stay in his room or leave and repeat what he has just been through. Dark and twisty with some great performances.
4. Primer (2004)
This ultra-indie ($7,000 budget) was a surprise hit as this movie uses its unique concept and surprisingly good acting for all that its worth. Four techies spend their nights and weekends creating a leading-edge error checking machine, but soon realize they have inadvertently created something much, much more. A power struggle ensues between the men as they begin to each use their newly found time machine to influence their own futures. Primer is truly a movie that exceeds its expectations and is definitely worth a watch for fans of this subgenre.
3. Back to the Future Trilogy (1985 / 1989 / 1990)
This classic trilogy of movies had the perfect mix of simple enough for general non-science audiences to understand and science-y enough for geeks like me to really drive our imaginations. Marty McFly (Michael J. Fox) goes back in time with the help of Doc Brown (Christopher Lloyd). In the first he needed to ensure that his parents hooked up to ensure his own existence. In the second he goes to the future to help out his future self from going to jail, but that trip causes changes to the past creating a messed up present (still with me?) - all of which he needs to fix as well. In the third, he needs to head to the wild, wild west - in the era which Doc now lives with his family - and needs to save him from being shot by the local baddie. These are all really less science and more fun, but either way it works!
2. Triangle (2009)
1. Timecrimes (2007)