Known as the "literature of ideas," science fiction is one of my favorite genres, full of innovation and imagination. It asks the question what if? and doesn't seek to provide answers but rather to provoke thoughtful explorations of space, time, and what it means to be human.

Here are 25 of my favorite sci-fi movies from the last two decades:

+1 (2013) directed by Dennis Iliadis

Take Los Cronocrimenes and Can't Hardly Wait, stick it in a sack, and shake it all around. What you're left with is +1, a creepy sci-fi puzzle wrapped in a teen party movie. When a meteor flashes across the sky, unsuspecting and self-absorbed party goers come face-to-face with their doppelgängers. Looking for a double feature? Try pairing this film with its upscale variant, Coherence.

Featuring Rhys Wakefield, Ashley Hinshaw, Natalie Hall, Logan Miller, and Colleen and Suzanne Dengel.

Coherence (2013) written and directed by James Ward Byrkit

During an astronomical event, three couples at a dinner party experience strange phenomena and work together to unravel a disturbing mystery. Rather than create a script, Byrkit wrote a short treatment and provided actors with carefully composed character notecards before inviting them to his home to film. Undaunted, these actors managed to create remarkably convincing performances using largely improvised dialogue. Pairs well with +1.

Featuring Emily Baldoni, Maury Sterling, Elizabeth Gracen, Alex Manugian, Lauren Maher, Hugo Armstrong, Lorene Scafaria, and Nicholas Brendon.

District 9 (2009) written by Neill Blomkamp and Terri Tatchell, directed by Neill Blomkamp

Nearly three decades after an alien spaceship arrives, Johannesburg is a city struggling with clashes between its local human citizens and alien inhabitants. When a bureaucrat is accidentally sprayed with an alien substance, he experiences biological changes and becomes the target of a manhunt. A thrilling debut from Blomkamp, District 9 is an action sci-fi film with a lot on its mind, delving into issues of identity, segregation, and xenophobia. My hope for District 10 is deep and fervent, withstanding even the onslaught of Chappie (evidence that the film gods are indeed cruel and capricious).

Featuring Sharlto Copley, Jason Cope, and David James.

Dredd (2012) written by Alex Garland and directed by Pete Travis

A sleeper hit that's well on its way to a cult classic, this Judge Dredd adaptation leaves the eponymous 1995 film in the dust. A law enforcer and his newly recruited partner are tasked with bringing order to a slum tower overrun by violent thugs. This film lovingly pairs blood and gore with beautifully rendered slow motion sequences and a hauntingly distorted musical score. Dredd is my go-to sci-fi action flick and is eminently rewatchable. Karl Urban might be old and gray by the time a sequel gets made, but as long as he keeps that implacable chin in good shape, we'll never know the difference.

Featuring Karl Urban, Olivia Thirlby, Lena Headey, Wood Harris, and Domhnall Gleeson.

Edge of Tomorrow (2014) directed by Doug Liman, based on All You Need Is Kill by Hiroshi Sakurazaka

In a war between humans and aliens, an incompetent soldier gains the ability to "reset" the day after killing an alpha alien. The soldier, trapped in a Groundhog-Day-like time loop, must improve his fighting skills after each reset in order to save humanity. Accompanying him in battle is a tough, sword-wielding veteran with the delightful moniker "Full Metal Bitch." This is a fun, blockbuster movie that will appeal to gamers (especially Halo fans) and non-gamers alike.

Featuring Tom Cruise, Emily Blunt, Bill Paxton, and Brendan Gleeson.

Ex Machina (2015) written and directed by Alex Garland

Ex Machina is an intellectual thriller that proves science fiction doesn't need an intergalactic setting or action-packed fight scenes to be deeply engrossing. A programmer is invited by his company's CEO to administer the Turing test to an eerily human-like robot. Smart and spare, this movie eschews the green screen in favor of provocative ideas and mesmerizing performances.

Featuring Alicia Vikander, Domhnall Gleeson, Oscar Isaac, and Sonoya Mizuno.

Futurama: Bender's Big Score (2007) created by Matt Groening, written by Ken Keeler and directed by Dwayne Carey-Hill

The first in four movies that comprise Futurama's fifth season, Bender's Big Score never saw a theatrical release but is an enjoyable film that shows the range of the genre. Sci-fi isn't always just creepy aliens and trippy time travel; sometimes it's also silly one-liners and alcoholic robots with shiny metal posteriors. One of the few animated series that can make me cry as hard as I laugh, Futurama is not to be missed. (Fans of the series should also check out Adult Swim's Rick and Morty.)

Featuring the voices of Billy West, Katey Sagal, John DiMaggio, Phil LaMarr, and Lauren Tom.

Galaxy Quest (1999) written by David Howard and Robert Gordon, directed by Dean Parisot

Sigourney Weaver, Alan Rickman, and Tim Allen all in one movie? Surely an embarrassment of riches! The cast of a canceled television series reunite for a convention but are kidnapped by an alien space crew that needs their help. Once voted the seventh best Star Trek movie, Galaxy Quest is an entertaining intergalactic adventure that both parodies and pays tribute to the sci-fi classic and its ardent fandom. A perfect starter film for those new to the genre.

Featuring Tim Allen, Sigourney Weaver, Alan Rickman, Sam Rockwell, Tony Shalhoub, Enrico Colantoni, and Justin Long.

Gattaca (1997) written and directed by Andrew Niccol

Set in a eugenics-based future where DNA rather than ability determines your place in society, a genetically-inferior "in-valid" goes to dangerous lengths to achieve his dream of space travel. One of my all-time favorite films, Gattaca defines all that is wonderful about the sci-fi genre, highlighting the ambition and determination of an individual to not only survive but excel despite incredible obstacles. It also features a young Jude Law at his very sneery best.

Featuring Ethan Hawke, Uma Thurman, Jude Law, Loren Dean, Ernest Borgnine, Alan Arkin, and Gore Vidal.

The Host (2006) written by Baek Chul-hyun and Bong Joon-ho, directed by Bong Joon-ho

A young schoolgirl is abducted by a reptilian creature during a bloody rampage and her misfit family must band together to save her. Scary, funny, and heartbreaking, The Host is a South Korean film that will leave your heart in your throat. You'll root for the bumbling family and shudder at the genuinely horrifying creature in one of the best monster movie of any decade.

Featuring Song Kang-ho, Byun Hee-bong, Park Hae-il, Bae Doona, and Go Ah-sung.

Inception (2010) written and directed by Christopher Nolan

With its distinctive sound effects, Inception dazzles with sumptuous visuals and a superb cast. Like the popular Ocean's Eleven trilogy and The Italian Job, Inception is at its core a heist film (though darker, weightier, and more thrilling). But unlike the standard heist flick, the impenetrable safe these thieves are trying to crack is buried deep within the subconscious mind and the money cache is nothing more than a secret thought, implanted rather than stolen, and meant to influence the victim's waking actions. With folding Parisian streets, spinning corridors, disintegrating cities, and a snowtop fortress, this film deserves multiple viewings.

Featuring Leonardo DiCaprio, Marion Cotillard, Ken Watanabe, Joseph Gordon-Levitt, Ellen Page, Tom Hardy, and Cillian Murphy.

Interstellar (2014) written by Jonathan Nolan and Christopher Nolan, directed by Christopher Nolan

A crew of astronauts must search for a habitable planet to save humanity from extinction. This is another Nolan film full of stunning visuals and no dearth of expositional dialogue. Whereas Inception explores the infinite mind, Interstellar takes on the incredible vastness of space (providing one notably breathtaking depiction of a supermassive rotating black hole). With theoretical physicist Kip Thorne consulting on the film, Interstellar maintains a degree of scientific accuracy that only enhances the central story surrounding a father and daughter relationship tested by time and distance.

Featuring Matthew McConaughey, Anne Hathaway, Jessica Chastain, Casey Affleck, John Lithgow, and Michael Caine.

The Iron Giant (1999) directed by Brad Bird, based on the novel by Ted Hughes

A giant alien robot falls from space and is befriended by a young boy. Nominated for the Hugo, Saturn, and Nebula awards and winner of a BAFTA, The Iron Giant has been consistently ranked as one of the best animated films and even enjoyed a brief revival in theaters recently. Set in the 1950s, the animation style is reminiscent of that time period, with beautifully composed scenes worthy of Rockwell and Hopper. Featuring my favorite Vin-Diesel-voiced robot, The Iron Giant is a must-see that will warm even the coldest of hearts. Brad Bird fans will also enjoy his other work including The Incredibles and Ratatouille (and Mission Impossible: Ghost Protocol!).

Featuring the voices of Eli Marienthal, Christopher McDonald, Jennifer Aniston, Harry Connick, Jr., John Mahoney, and Vin Diesel.

Looper (2012) written and directed by Rian Johnson

In the future, criminal gangs utilize time travel to send victims to the past to be killed by specialized assassins or "loopers." One looper discovers that his next target is his future self and must deal with the consequences of his actions. Why Joseph Gordon-Levitt had to be rendered nearly unrecognizable to play a young Bruce Willis, I'll never know. Slip in some blue contacts and I would have called it a done deal. That aside, Looper does an excellent job handling the inherent intricacies of time travel and not letting it overwhelm the story. Stylish and smart, Looper is an impressive addition to the sci-fi genre by Brick and future Star Wars: Episode VIII writer and director Rian Johnson.

Featuring Bruce Willis, Joseph Gordon-Levitt, Emily Blunt, Paul Dano, and Jeff Daniels.

The Martian (2015) directed by Ridley Scott, based on the novel by Andy Weir

Left for dead on Mars, a lone astronaut has to figure out a way to survive with limited resources. With the emphasis on the "science" in "science fiction," this is a pleasingly faithful adaptation of Weir's wonderfully geeky debut novel. Mark Watney is a refreshing protagonist, unflappably determined and good-humored despite near insurmountable odds. If I were trapped on Mars, I'd spend most of my days curled up in a fetal position drowning in an epic existential crisis before bitterly starving to death. The movie adaptation would have been a disgrace.

Featuring Matt Damon, Jessica Chastain, Kristen Wiig, Jeff Daniels, Sean Bean, Michael Pena, and Chiwetel Ejiofor. (All that star power but no Ben Affleck cameo? Disappointing! Doesn't the world know that Affleck and Damon belong together like Kirk and Spock, Burke and Hare, Achilles and Patroclus?)

Moon (2009) written by Nathan Parker and directed by Duncan Jones

An astronaut experiences strange occurrences as he nears the end of his three-year work contract on the moon. Sam Rockwell's name is like a quality assurance guarantee: stellar performance promised, stellar performance delivered. I've never met a Rockwell film (or play) that I didn't like, and this movie doesn't disappoint. With smart direction and a sharp script, Moon is a fascinating and thoughtful addition to the hard sci-fi oeuvre.

Featuring Sam Rockwell, Dominique McElligott, and the dulcet tones of Kevin Spacey.

Pacific Rim (2013) written by Travis Beacham and Guillermo del Toro, directed by Guillermo del Toro

Giant robots. Need I say more? You don't have to be Grant Imahara to appreciate the delightful pulpiness of this movie. Starring Idris Elba and Charlie Hunnam (whose withdrawal from the Christian Grey role was both a relief and a disappointment), this movie may be weak in dialogue but powers through with fantastic action scenes that translates to any language. Again, robots smashing things? 10 out of 10 stars.

Featuring Charlie Hunnam, Idris Elba, Rinko Kikuchi, Charlie Day, and Ron Perlman.

The Prestige (2006) directed by Christopher Nolan, based on the novel by Christopher Priest

Two rival stage magicians play a lethal game of one-upmanship in 19th century London. At the risk of revealing too much, I'll simply say that this isn't your Tony Wonder vs. G.O.B. kind of dueling magicians. Dark and unsettling, you'll be contemplating the film's implications long after the final credits.

Featuring Hugh Jackman, Christian Bale, Rebecca Hall, Scarlett Johansson, Michael Caine, Andy Serkis, and David Bowie.

Primer (2004) written and directed by Shane Carruth

Filmed on a meager $7,000 budget, Primer provides a seriously mind-boggling examination of time travel. There is no audience surrogate or Nolan-esque expositional dialogue to gently introduce complex ideas and intricate plot points. From the first scene, you're thrown into the mix, and just when you think you've got a handle on what's happening, think again. Primer isn't an easy ride but the payoff is worth it.

(Watched the film and still perplexed? Randall Munroe, creator of webcomic xkcd, provides an elucidating graph to help parse the timelines.)

Featuring Shane Carruth and David Sullivan.

Serenity (2005) written and directed by Joss Whedon

The bitterness I carry against FOX for canceling Firefly is as deep and vast as Ganymede's subterranean ocean. Serenity (an excellent palliative, but a palliative nonetheless) continues the story of a scrappy crew of smugglers led by a hardened war veteran. A fantastic mash-up of the space opera and western genres, this is another Whedon classic with shrewd practical effects and distinct characterization that will appeal to fans of Buffy the Vampire Slayer, Angel, and Marvel's Agents of S.H.I.E.L.D.

Featuring Nathan Fillion, Alan Tudyk, the divine Gina Torres, Morena Baccarin, Adam Baldwin, Summer Glau, and Chiwetel Ejiofor.

Snowpiercer (2013) written by Bong Joon-ho and Kelly Masterson, directed by Bong Joon-ho

Based on the unremittingly grim French comic book Le Transperceneige by Jacques Lob and Jean-Marc Rochette, this South Korean film features an international cast and a dystopian premise. With the world frozen in a manmade ice age, the last of humanity fights for survival on an unstoppable train, the Snowpiercer. Rigidly segregated by class, front-end elites live in splendor while the tail-end passengers live in squalor. Revolt is inevitable, and like its characters, this film walks the fine line between brilliance and madness.

Featuring Chris Evans, Tilda Swinton, Song Kang-ho, Jamie Bell, Go Ah-sung, Octavia Spencer, and a perpetual-motion engine.

Time Lapse (2014) written by Bradley D. King and B. P. Cooper, directed by Bradley D. King

If there's anything to learn from sci-fi films, it's this: If you stumble across a time machine, leave it alone! Trust me. Nothing good will come of it. You know why you don't see octogenarians meddling with the space-time continuum? Because they're old enough and wise enough to say, "Nuh-uh, hard pass." Three young friends find a machine that produces photographs taken 24 hours into the future. Do they prudently and judiciously use this amazing machine to fulfill their lifelong ambitions and live a life of peace and luxury? Hmph.

Featuring Matt O'Leary, Danielle Panabaker, and George Finn.

WALL-E (2008) written by Andrew Stanton and Jim Reardon, directed by Andrew Stanton

Not since the Iron Giant have I ever wanted to hug a robot so hard (an unpleasant experience, surely, with all those sharp edges and metal bits). A lone robot spends his time cleaning an abandoned, unlivable Earth until one day another robot appears and leads him on a life-changing journey into outer space. Breathlessly beautiful, Wall-E is another Pixar creation that will charm and enthrall people of all ages.

Featuring the voices of Ben Burtt, Elissa Knight, Jeff Garlin, Fred Willard, John Ratzenberger, Kathy Najimy, and Sigourney Weaver.

The World's End (2013) written by Edgar Wright and Simon Pegg, directed by Edgar Wright

One of the true pleasures of this movie was watching it in a packed theater with my brother (who occasionally masquerades as an adult) and listening to his uncontrollable laughter and shocked gasps at every twist and turn. An ambitious pub crawl in the town of Newton Haven leads a group of alienated friends on a legendary adventure. If you love Shaun of the Dead and Hot Fuzz, you'll love this hilarious conclusion to the Cornetto trilogy.

Featuring Simon Pegg, Nick Frost, the amazing Paddy Considine, Martin Freeman, and Rosamund Pike.

The 25th and final slot I've left open in anticipation of The Lobster, a satirical sci-fi comedy that I've been impatiently waiting to hit theaters. Directed by Yorgos Lanthimos and written by Lanthimos and Efthimis Filippou, The Lobster was released abroad in 2015 and will hit US theaters in March 2016. It's already snagged the 2015 Cannes Film Festival Jury Prize and has enjoyed critical accolades (including a BAFTA for Olivia Colman!). Featuring Colin Farrell and Rachel Weisz, the film depicts a city where single people must find a partner within 45 days or face being turned into an animal and released into the wild. Just give me a showtime and take my money already!