I challenge http://www.youtube.com/watch?v=JN99jshaQbY&feature=feedf

To explain Donnie Darko.

I'll stay on topic by saying that Donnie Darko might be about time travelling and I know its not the type of that was asked, but I feel that everyone should see it at least once. I also feel the same way about Memento(which is another confusing-to-some movie that I have no theories about because I completely understand it).

To stay even more on topic the Hitch Hiker trilogy has a fair amount of time travel in it.

I don't think the time-travel aspects of Donnie Darko are all that hard to explain. The evil bunny on the other hand... I'm not sure that Richard Kelly is really the type to make his movies 100% explainable, though. I mean, just look at Southland Tales. :blink:

Donnie Darko and Twelve Monkeys are definitely very entertaining movies. I found Primer to be more thought-provoking than either, though, and it was made on a $7,000 budget!

There was a story somebody was writing on Reddit about a modern day marine unit transported to Roman times. I think it was called 'Rome Sweet Rome'. It was fairly interesting. I think I read that Warner Brothers actually bought the rights to the story.

Edit: Also, I don't know if you are a fan of Star Trek, but there was a whole arc on 'Enterprise' that dealt with aliens going back in time to influence the second world war and the Enterprise crew trying to stop them.

I know it doesn't have armies or anything like that in it, but a really good time traveling movie I enjoy is "The time Machine." Yes the special effects aren't up to par, but it has a great and original story line that I haven't seen in any other type of movie. really good!

Well, the Hitchiker's Guide to the Galaxy series had the Cricket Wars

But

The Hyperion series of books is steeped with time travel, but I can't remember how or if the series matches your criteria. It got pretty convoluted, and it was a long time ago that I read it. I remember an army from the future fighting another, and a few characters traveling through it...that about all I can give you.

From the second book, The fall of Hyperion:
After making contact with other Ouster humans from this future, he attacks the Shrike again as his new allies attack legions of other Shrikes that have come into existence, in a battle to decide if "humanity gets a say in its future". Although this future humanity apparently wins the battle, Kassad is killed.

Its been a few of years since I've seen it, but I think Donnie Darko is about

Note to the OP: When the Hitchhiker Trilogy is mentioned it is about the book. Do not under any circumstances see the movie, it made me lose so many Hope Points for adaptations that The Lord of the Rings had built up.