Most people are familiar with the greatest films in the science fiction genre, but you might be hard-pressed to name any of the best sci-fi cult classics of all time. You may ask "what differentiates a cult classic from a regular old classic?" After all, both classics and cult classics have great lines, great scenes, a loyal fanbase. What's the difference?

Cult classics are the dark horses of cinema – underrated by mainstream audiences. They either flopped at the box office or the film's marketing campaign didn't work right. But, over time, thanks to the advent of the video rental market and internet, the films found an audience. A cult audience, if you will.

Most cult classic films walk to the beat of their own drum. They may be off-kilter, odd, or even a little crazy. They may be offensive or silly – hell, even both. But there is that spark of quality that speaks to a certain audience.

Sci-fi is, by nature, an off-kilter genre. A lot of great underrated sci-fi films may not earn mainstream success, but they earned a great cult following.

Unsure where to start? While there are hundreds of great sci-fi cult classics, we have compiled a list of the best sci-fi cult classics of all time – the ones that every self-respecting sci-fi fan needs to see (even if a few of them are little too weird for you).

Dystopian films are a dime a dozen now – thanks to mainstream hits like The Hunger Games – but back in the 70s, people had odd thoughts about where the future would lead us. Logan's Run, one of the best sci-fi cult classics of all time, is probably the quirkiest and oddest dystopian film you will ever see.

Starring 70s legends Michael York (Austin Powers) and Farrah Fawcett-Majors (Charlie's Angels), this 1976 classic presented an idyllic futuristic life. Everyone is happy, able to eat and drink whatever they want.

Oh, the drawback is you have to kill yourself when you turn 30 years old.

Those who try to escape their fate – the Runners – are chased down and killed. Michael York plays Logan, a man who is on a mission to find a sanctuary of Runners – not to join them, no. His job is to hunt them all down and kill them. The only problem is that the computer just made Logan turn 30...

Though the film won an Academy Award for its effects back in the day, the effects have aged terribly. Few of the effects are convincing, and the costumes look silly. Fans of sci-fi may take great pleasure in how silly the whole film is. It's a must-watch film for sci-fi cult classic fans.

Silent Running presents a future where plant life on Earth is extinct. Green flourishes only in a set number of space ships, maintained by scientists preserving Earth's ecosystem. When they are told to dump the greens in order to make room for supplies, the scientists must fight to protect their plants.

Starring Bruce Dern, this sci-fi cult classic was commissioned by Universal. Following the success of Easy Rider, Universal saw the profitability of low-budget, anti-establishment films. They ended up making one of the best sci-fi cult classics of all time.

Considering how little money they had to make this film, Silent Running looks incredible. I suppose this makes sense, considering the director, Douglas Trumbull, did the special effects for sci-fi classics 2001: A Space Odyssey and The Andromeda Strain. Of particular note are a trio of robots who were, at the time, unlike any other robots on film. They put little people inside mechanical bodies and had them operate the machines from within. George Lucas would utilize the same effect when creating R2-D2.

While the environmental message is a little heavy-handed, the film found its audience in the years where the Hudson ran black with filth. Nowadays, with politicians reigning back the EPA, Silent Running is as important as ever.

This is exactly what the greatest sci-fi cult classics of all time should be made of. Social commentary, satirical humor, and lots of exploitation. The Brother from Another Planet may be written off as another blaxploitation film, but, to those willing to dig deeper, there's a lot to talk about here.

An alien who cannot speak crash-lands in Harlem. The alien looks just like a black man, which allows him to blend in. As he makes his way through New York, the Brother (Joe Morton) is chased through Harlem by intergalactic bounty hunters, intent on returning our Brother to the shackles of slavery.

Joe Morton's Brother offers viewers a lot to think about. Throughout the film, the alien is incapable of speaking – but most normal people don't seem to notice, as they just keep talking and talking.

On one hand, it's a funny depiction of how self-absorbed humanity is – but, on the other hand, it's also a decent political satire about how little political and societal say people of color had at that time – and, in many cases, still have.

Ever get tired how clean the Starship Enterprise looked on Star Trek? I mean, think about it: your car gets messy after a few weeks. Imagine how dirty a ship would get with all those people in it after a five-year journey.

Dark Star is one of the first sci-fi films to illustrate what "dirty space" would look like. This concept would later be perfected in films like Alien and shows like Firefly, but, before those sci-fi classics, this obscure film played around with the idea. As a result, it remains one of the best sci-fi cult classics of all time.

Stuck on a little ship, the crew of the scout ship Dark Star has slowly gone insane over the course of their 20-year mission. As they struggle to deal with the tedium of their very existence, their apathy toward the state of their ship and their surroundings may lead to their untimely demise.

The debut film by sci-fi and horror legend John Carpenter (get used to his name, since you're gonna see it a lot), this cult favorite wonderfully spoofs man’s view that he is the center of the universe showing us up to be incompetent, self-involved and ridiculous.

Robert Heinlein is often touted as one of the greatest science fiction writers of all time. Often compared to Isaac Asimov and Arthur C. Clarke, Heinlein's work in the 50s and 60s revolutionized the genre. Heinlein's 1959 novel Starship Troopers served as one of the best military science fiction novels ever written.

While highly conservative and pro-military, it presented a world that, regardless of if you viewed it as a utopian or dystopian society, made you question the way society worked.

Paul Verhoeven (director of sci-fi classics Robocop and Total Recall) read the book, and hated the message so much he decided to make, essentially, a spoof of the novel. Thus, the film version of Starship Troopers emerged.

The plot of both the film and book are very similar – bugs and space marines are at war. If you serve in the military, you will be given citizenship. Where Heinlein tried to tell a story of militaristic strength, Verhoeven tells a narrative about the dangers of propaganda and dictatorship.

The film is full of cult actors, including Neil Patrick Harris, Michael Ironside, Jake Busey... oh, yeah, and Casper Van Dien and Denise Richards. They're the main characters, I guess.

Incredible world-building, spectacular effects, terrifying bugs, stupidly gory deaths, and incredible political commentary, Starship Troopers earns its place among the best sci-fi cult classics of all time.

The original film that spawned four sequels, a remake, and a reboot trilogy, Planet of the Apes is an adaptation of a French novel, brought to the screen thanks in part to Rod Serling, the mastermind behind The Twilight Zone.

While many people quote the film ("Get your stinkin' paws off me, you damn dirty ape!") and know the ending, few people have actually watched the movie, which is a shame. This is easily one of the best sci-fi cult classics of all time.

Starring Charlton Heston and Roddy McDowell, Planet of the Apes tells of a tiny spaceship that crashes onto a planet run by apes. Humanity is a savage, oppressed race that cannot speak. Charlton Heston is the only sane man on this planet, and must find a way to return home.

The effects may be dated, but it is a testament to the film's amazing script that the movie remains a masterful social satire. Few sci-fi films can retain its intensity after all these years. At once awe-inspiring and tragic, Planet of the Apes is a must-watch film for any fan of science fiction.

Earth Girls are Easy is stupid. It's a dumb, ridiculous film by design. For a lot of mainstream viewers, it was too goofy and too silly to really strike a cord, but, for those off-kilter fans, it became a cult classic.

Starring then-lovers Geena Davis and Jeff Goldblum (and a complete unknown named Jim Carrey), this sci-fi cult classic stars three furry aliens who crash land in California. Obviously, a bunch of hairy aliens aren't going to fit in, so they get a makeover and start dating women.

It's awkward, a little uncomfortable, and kind of strange. But if you're looking into goofy sci-fi romantic comedies to watch, this is a decent place to start.

One of the best sci-fi cult classics of all time is also one of the best horror cult classics of all time. Re-Animator remains a classic years later thanks in part to its combination of science fiction horror and dark sense of humor (and I mean dark!).

Based on a story by genre legend H.P. Lovecraft, Re-Animator tells the story of a med student who's new flatmate enjoys reanimating the dead. Shockingly, it doesn't go well. Starring the always-entertaining Jeffrey Combs, this 80s cult classic is a grotesque masterpiece.

Look, I'm going to be up front about this. If you don't find zombie cats, headless corpses trying to have sex, and comedically timed decapitation funny, you might not find this film as funny as a lot of fans did...w hich is why this film probably never received mainstream acclaim. But for those of us with a really, really, really sick sense of humor, Re-Animator is one of the best.

You wouldn't think the guy who directed Babe and Happy Feet would make a film about murder, hatred, and death – but, lo and behold, George Miller's first film was Mad Max, a low-budget sci-fi film about cars and the apocalypse. This cult classic, for a time, was the most financially successful Australian film of all time. It has since become a sci-fi cult classic franchise.

Starring a baby-faced Mel Gibson, this Australian classic offers a bleak view of a dystopian world overrun by violence. Gibson plays Max – a police officer hellbent on destroying a biker gang after the murder of his wife and son.

I'm gonna be honest with you. Mad Max may be one of the best sci-fi cult classics of all time, but its sequels are arguably even better. Mad Max 2: The Road Warrior single-handedly invented a sub-genre of post-apocalyptic cinema. Mad Max: Fury Road is one of the most action-packed and bad-ass (and surprisingly feminist) sci-fi films in a long time. If you like the original, I strongly urge you to also watch both films, as they up the ante of the original.

And Mad Max: Beyond Thunderdome is worth watching even if it's the weakest of the series.

The oldest movie on this list, Forbidden Planet was made in 1956. While the plot is essentially a sci-fi adaptation of William Shakespeare's The Tempest, Forbidden Planet was eons ahead of its time.

This classic stars Walter Pidgeon, Anne Francis and Leslie Neilsen (yes, the same one from Airplane and The Naked Gun), and tells a story of a spaceship crew that are investigating a seemingly abandoned colony. The only people remaining is a wise man, his daughter, and a robot. Again, it's the plot to The Tempest, only in space.

While the film itself is brilliant and well-written, its influence on the sci-fi genre cannot be understated. The film directly inspired Gene Roddenberry when he came up with Star Trek. The robot in the film is one of the first non-human, friendly robots in science fiction history.

And, even if none of that appeals to you, at least you can always say you're watching Shakespeare to your friends teasing you about your voyage through science fiction history.

Based on the George Orwell novel, the film adaptation of 1984 (released in the year 1984) never received the same critical acclaim of the novel. It's a real shame, too, because this film really brings Orwell's nightmare world to life.

This film stars the great, late-John Hurt as Winston, one of the few sane men in a dark totalitarian future where Big Brother watches all and free thought is outlawed. Our hero dares defy the laws that bind human nature, and, as a result, is subjected to horrors beyond imagining.

The film incorporates many elements of 80s science fiction in order to bring Orwellian society to life. It really is a bone-chilling movie – perhaps a little too bone-chilling. While the novel is considered a masterpiece, the movie warded off many people by being simply too bleak to handle. As a result, mainstream audiences missed out on a great social satire, leaving it to become one of the best sci-fi cult classics of all time.

Let's talk about John Carpenter again. Carpenter's films seem to come in two varieties: dark comedy and dark horror. While none of Carpenter's films can be considered mainstream classics (except maybe Halloween), he has found his audience among genre fans for his consistently great films.

They Live is not one of his best films. Don't get me wrong: it's great. But Carpenter has done better. But the social satire presented in the film is harsh, biting, and hilarious. And, for that alone, it's one of the best sci-fi cult classics of all time.

This late 80s film tells the story of a loner who finds a pair of magic sunglasses that exposes subliminal messages left by aliens to control mankind. "CONSUME! PAY MONEY! OBEY!" As the only man who sees the truth, it's up to this weirdo to save the world.

Starring the late-Roddy Piper and cult star Keith David, the film is incredibly quotable, silly, and ridiculous. Where do we start with this film? That fight scene in the alleyway that just keeps going on? The "chew bubblegum and kick ass" scene? You simply haven’t completed your cult list until you’ve seen this film.

So few of the movies on this list of the best sci-fi cult classics of all time star a woman as the central character. While a lot of the greatest sci-fi movies films star incredible women (Aliens, The Terminator, Ghost in the Shell), there are sadly too few cult classics starring women. I think this has to do with the era when many of these films are made. If Mad Max: Fury Road is any indication, the sci-fi cult classics of tomorrow will rectify this mistake.

But there's always Barbarella. Yes, Barbarella – an exploitative film where Jane Fonda takes her clothes off, spins around in zero gravity, has a ton of sex, and, in the end, is tortured by a machine that overloads your body with orgasms until you die.

I can't make up this crap.

Needless to say, feminists were not impressed. This movie is about as silly and dumb as it gets, bordering on soft-core porn from beginning to end. However, some feminists have rediscovered the film (and the French comic it's based on), claiming its sex-positive themes are, in some way, empowering. I'll leave you to be the judge on whether or not you agree with them.

Terry Gilliam, former Monty Python animator and master of dark and strange cinema, produced an Orwellian vision of a world where a bureaucrat manages to make himself the enemy of the state.

When you look at that on paper, you may say "So what? What's so odd or interesting about that?" It truly is hard on paper to explain why Brazil is one of the best sci-fi cult classics of all time.

The film incorporates a strange sense of humor, through its visuals, music, acting – everything. It presents a corporate world where human affairs are business as usual – an obvious reflection of then-modern society.

The film proved so weird that editors, upon release, cut out 40 minutes of film before it hit theaters. The chopped-up release proved very unsuccessful, but Gilliam's original vision found its audience. It is often regarded as one of the greatest movies ever made, but, due to its semi-obscurity and mangled release, has ended up as a cult classic. That's just as well, as most mainstream audiences probably wouldn't understand this one.

And the ending – well, the ending was so controversial Gilliam had to fight to keep it in the film. If you like bizarre science fiction, I urge you to watch Terry Gilliam's other sci-fi cult classics, 12 Monkeys and Time Bandits. Both are incredible films that remain too strange for a mainstream audience.

There are three movies called The Thing. There's the original from the 50s (a classic sci-fi film in its own right), John Carpenter's remake from the 80s, and a prequel to Carpenter's film from 2011.

We're talking about Carpenter's version, which many fans believe may be better than the original.

Scientists in Antarctica discover a Swedish base that has been ravaged by something. The only survivor is a dog – or at least, something that looks like a dog. In actuality, the dog is an alien life form that can replicate any organic matter – but can transform into a grotesque monster when provoked. The scientists are left wondering who among them has been replaced. And what might happen should this thing reach society.

The film stars 80s cult classic star Kurt Russell. Russell worked on many of Carpenter's greatest films, including Escape from New York and Big Trouble in Little China. But The Thing remains Carpenter's greatest work. Despite its minuscule budget, the effects remain unmatched.

Sadly, it flopped upon release. It only found its audience thanks to the video rental market, where it developed a reputation as one of the best sci-fi cult classics of all time.

If you are watching the best sci-fi cult classics of all time, you must watch Blade Runner. Often regarded as one of the greatest science fiction movies ever made, Ridley Scott's next sci-fi film after Alien was edited to shreds before release.

It failed to draw mainstream attention thanks to its heavily edited theatrical cut as well as the fact it came out in the same month as E.T. the Extra-Terrestrial and Star Trek II. Once the original director's cut (and, later on, the final cut) hit video stores, the film became one of the best sci-fi cult classics of all time.

Based on Philip K. Dick's Do Android Dream of Electric Sheep?, Harrison Ford plays Rick Deckard, a "Blade Runner" who hunts down Replicants – humanoid androids who spend their four years of life laboring away on off-world colonies. Replicants are illegal on Earth, so, when a group of them come to Earth seeking to extend their lifespans, Deckard sets off to "retire" the androids.

The film takes a few viewings to truly appreciate. What at first looks like a simple sci-fi noir film evolves into an exploration of human nature. When society can create computers with the capability to express and feel human emotions, then what divides them from us?

It is almost an understatement to call Blade Runner one of the best sci-fi cult classics of all time. It's one of the best movies ever made.

A football player and a ragtag group of his friends must travel to the planet Mongo to save Earth from Ming the Merciless.

That doesn't sound too complicated of a plot, does it? In fact, it's very simple. The movie is goofy, cheesy fun. A throw-back to a simpler era of science fiction.

In a genre full of great films, why would we put Flash Gordon on this list of the best sci-fi cult classics of all time? Surely it isn't just because the music by Queen. It can't just be because of the delightfully hammy Brian Blessed in a minor, yet quotable, role.

I'll explain. Flash Gordon is one of the cornerstones of science fiction as a genre. Not this film, but, rather, the source material. Countless filmmakers, including George Lucas, would watch and read the adventures of Flash Gordon. It inspired them to create their own stories decades later. There's a real possibility that, without this character, sci-fi as we know it would not exist.

Flash Gordon may be a weird movie. It may be a racially insensitive movie. And it may have one of the coolest theme songs of all time – courtesy of the legendary Freddie Mercury. But it is also a time capsule of an era long past. It takes us to the beginnings of the genre.

And, for that reason alone, it's one of the best sci-fi cult classics of all time.