A scavanger and a doctor use time travel in order to prevent an organization known as the "Army of the 12 Monkeys" from unleashing a plague upon the world. This series has graced us with a great premise and solid writing, prompting a strong following for 3 seasons, and will be given a proper send-off with a fourth and final season in 2018.
Doctor Sam Beckett, a volunteer in a time travel experiment finds himself leaping throughout time and different lives, attempting to change those lives for the better. This 1989 series was well cast, well written and well ahead of its time (pun intended).
Following a similar premise, this series involved an ordinary newspaper reporter that inexplicably begins jumping back and forth through time. He eventually learns that he is destined to change the past lives that he comes in contact with.
Terminator: The Sarah Connor Chronicles
From a blockbuster franchise to spinoff series, The Sarah Connor Chronicles was a load of fun. Although it retained none of the cast of the films, Thomas Dekker and Lena Headey did John and Sarah Connor enough justice that it managed to squeak out two seasons that appeased the most die hard Terminator fans.
A short lived series from the early 1980's that lasted only one season. This tale involved a man named Phineas Bogg, who was part of a group of time travelers knownw as Voyagers. With the help a young boy named Jeffery, the two traversed time in order to ensure history unfolded as it should.
Big things come in small packages. This miniseries, based on the Stephen King novel of the same name, tells the story of an English teacher who is offered the chance to travel back to 1963 in an attempt to prevent the assassination of JFK.
With a series involving James Franco, J.J. Abrams and Stephen King, what's not to love?