Stargate SG-1 anyone? Start with episode Moebius; then fast forward to the final episode of the series with Teal'c magically being able to be kept out side the reversing time dilation field, and to somehow go past the point it was turned on (even though Carter said that was impossible) AND the big one, what happened to his 'younger' native to that time frame self? After all, he's the older version of himself in the movies...
Stargate Atlantis, Shepard rescued by hologram of old McKay very far in the future; don't forget the dimension jumping episode a la Sliders. Then came Stargate Universe (didn't really like, btw), in which the Destiny has what? Two temporal loops?
But the best one has got to be "Seven Days". Take an alien space craft, reassemble it into a time machine limited to only 7 days that it can retroactively jump (which, I can't remember if he ever went forward...only back I think), and go fix terrorist attacks, assassinations, and other such disasters...yup, every single episode is a gigantic paradoxical plot hole.
Love Dr. Who though, so, even though it hurts the mind a bit, time travel is fun.
The Transformers 1980s series has one that's also given me a headache.
Megatron traps the Aerialbots in the past because their flying skills are making monkeys out of Starscream and his Seeker Squadron. Back in time they go through the events that eventually lead to the creation of Optimus Prime. Now then....
What started this thing? How did Optimus Prime end up being created in the first place when the Aerialbots hadn't existed yet (they were built in the future).
Then again it was just a cartoon to market toys and children back then didn't pay too much attention to the problems in the stories...
Oh! I can't beleive this one didn't get mentioned much before, Terminator. Each time someone travels back in time it changes the timeline irrevocably. This got mentioned in several eps when they discovered that some people came to the past from a different future than Derek Reese came from. Therefore... It's a ball of wibbly-wobbly, timey-wimey stuff. So yeah, T:SCC and Salvation are in the same universe. But temporal incursions changed the present and erased one from history.
I still miss SCC, it would be cool to know how it would've continued like the way Defying Gravity's creator did
Yeah really. I was so bummed to see it get cancelled just when it was getting so good. I really wanted to see what the T-1001(Weaver) was going to do in the future. Also.... what she was planning in general would have been nice to know..... She wanted to fight Skynet by building a better(but presumably nicer) rival to Skynet? Color me intrigued.
The way I see it, all of these timelines exist separately, with any interactions between them being predetermined (and indeed the actions within the timelines). Essentially each action (each movement of the smallest subatomic particle, and there is logically no smallest subatomic particle) in each smallest fraction of time (again, there is no such thing) has it's own timeline. Kinda like Douglas Adams comedically portrayed it
Infinite possibilities have implications that could not be completely understood if you turned this entire universe into a giant supercomputer.