“Planet of the Apes" (1968)
“Damn you dirty apes, damn you all to hell!” barks Charlton Heston as Col. George Taylor in one of cinema’s greatest endings. Prior to that, we had seen the ruins of a future earth, now ruled under a hairy paw, with primates enslaving humankind and reorganizing the food chain. “Planet of the Apes” at times feels like a relic of an era reflecting great social change, but it’s this sober-headed sensibility that makes the absurdity of the premise palatable, and the gravity (and, yes, hamminess) of Heston’s portrayal that gives the picture a genre movie gravitas. An unquestionable highlight of an exciting era in genre filmmaking, even if the actual time travel science performed countless somersaults in a series of sequels. [A-]

“Primer" (2004)
When cubicle co-workers take advantage of their free time and programming understanding, they create a device that allows them to travel through time, essentially multiplying themselves. Shane Carruth’s chilly debut, however, takes things in more cerebral, sinister directions, creating genuine horror out of the belief that, yes, anything is possible. You may need multiple viewings to fully parse what’s going on in “Primer,” which never slows down to allow the audience to decipher the possibilities present. We’re sadly still waiting for the follow-up from Carruth, who has struggled to find financing, though the no-budget “Primer” has more inventiveness and ideas than any of the science fiction films in the last decade. [A]

“Somewhere in Time" (1980)
Also known as your mom’s favorite time travel movie, “Somewhere in Time” is a swoony, sci-fi-inflected romance written by “Twilight Zone” regular Richard Matheson. But rather than employing other ‘80s time machines like a DeLorean or a phone booth, our hero Richard Collier (Christopher Reeve) simply uses his mind and hypnotizes himself into traveling to 1912, where he meets the object of his affection, then-famed actress Elise McKenna (Jane Seymour). They fall in love despite objections from her manager (a stern Christopher Plummer), but the ever-looming present is more of a threat to their romance. You’ll either laugh at the over-the-top silliness or well up with tears every time John Barry’s Rachmaninoff-inspired score swells, but “Somewhere in Time” is a cult favorite for the romantic set. We’ll give it a mediocre grade, but that doesn’t mean we’re not swayed. [C+]

“The Terminator" (1984)
James Cameron’s iconic sci-fi action thriller is not strictly a time-travel oriented film but the adage does factor significantly into the entire saga. For those who have not seen the film, this writer is about to spoil the franchise. Scrappy and resourceful Kyle Reese (Michael Biehn) is sent back in time to save one Sarah Connor (Linda Hamilton), mother of John Connor, the leader of a human resistance in a desolate future where artificial intelligence has blossomed and corrupted into a death factory bent on the eradication of humanity. What follows is a series of brilliantly escalating set pieces as Kyle and Sarah are pursued by The Terminator (future governor Arnold Schwarzenegger), a full-on killing machine. Time travel is rarely mentioned in the film, but the echoes of Kyle’s trip reverberate throughout the films that followed and permanently impact the fate of Sarah and her unborn child. Also, the glimpses of the future that Cameron does show are nifty, though eclipsed by the sequel’s massive visual overhaul. [A-]