Terminator 2: Judgment Day (1991)
Killer robots sent back from the future to kill our only hope at surviving their nuclear automated apocalypse, which is still to come. Not a bad idea, and as they say the execution of an idea is what makes it great – James Cameron and Arnold Schwarzenegger do that perfectly in Terminator 2. The liquid metal T1000 helps.
Star Trek: First Contact (1996)
Star Trek prides itself on accurate portrayals of future tech to the point of employing scientists to help write the scripts. So when it comes to time travel, hopes run high. First Contact sees the crew of the Enterprise follow a Borg ship through a vortex to go back in time and save the first warp drive launch from being sabotaged by Borg – which leads to the important growth of our race as an intergalactic presence. Not a loose end in sight.
A Connecticut Yankee in King Arthur's Court (1949)
Based on the Mark Twain novel, the A Connecticut Yankee in King Arthur's Court is a witty time travel tale of a singing mechanic (Bing Crosby) from 1912 who finds himself back in the days of King Arthur. Using his knowledge of science, the time traveller is made boss and fits in as a Merlin-like character whose use of a lighter is God-like. Funny and clever, a must see classic.
Time Bandits (1981)
Time travel is far too serious for its own good sometimes, whereas Time Bandits isn't serious at all. If we'd started scripting a time travel movie we would have started with lasers, eight o'clock, day one.
Butterfly Effect (2004)
No time machine required, just a bit of focused nostalgia as Ashton Kutcher tries to make the present better by meddling in the past. If the movies have taught us anything, it's that no good can come from meddling in the past. Shame no-one told Ashton that.