I scanned my hometown film festival's schedule for science fiction or fantasy films. There were none.

Of course, I thought, since my home town is not Cannes, Park City, or Toronto, we only attract the smaller films, and you can't make a good spec-fic flick on a budget.

And then I thought again.

Primer. Cube. Habit. The American Astronaut. Science Fiction. The Navigator. Time Crimes. The Blair Witch Project...

It's possible to write not only a cheap science fiction film; it's possible to write a good, cheap science fiction film. In hopes of inspiring more spec fic at next year's film festival, here's some advice to screenwriters based on past successes.

1. Keep the Budget in Mind.

Necessity is the mother of invention, and poverty is an incubator for creativity. As a writer you can help your director and producers by knowing that talk is cheap--compared to spaceships and dragons.

Primer(2004) and Timecrimes(2008) are time travel movies. But rather than filming ancient Egypt or Blade-Runner L.A., these films keep the time horizon close. Since both have a modern setting, they are easy to shoot. You don't need convincing costumes, special effects, or vintage cars on every street. Both involve loops and Zs scratched into the natural timeline that are only a few hours long. The resulting paradoxes make for engaging plots and mind-blowing revelations without the need for anything more convincing than a homemade time machine and the occasional lookalike stand-in for characters who meet their previous selves.

Another inexpensive time-travel movie is The Navigator (1988), which brings a small number of medieval peasants to the present. The production required a half-dozen convincing costumes and one windswept landscape (no power poles or asphalt, please). Instead of a time machine, the characters walk through a tunnel in the earth that emerges into the present day. One of the elders has known of the tunnel and kept it a secret, but a deadly disease sends them through to the Other Place on a quest to appease God and free them from the plague. One of the writer's tricks I liked best is that the medieval characters were able to take our modern technology in stride. They were surprised to see electricity and steel and automobiles, but they took it for granted that people needed light, building material, and transportation.

A German film called Science Fiction (2003) creates a Groundhog Day-like situation. After a seminar, two colleagues find themselves trapped in a parallel universe where they are remembered by the locals only as long as they're in the same room. The "science fiction" in the film lives entirely in the writing and acting, and not at all in the sets, costumes, or special effects. And yet the device is rich enough to fill a feature-length plot.

Two more ideas spring to mind: The Blair Witch Project's whole concept is that its characters were making a film with no budget. Thus their footage is completely justified in looking cheap. And you can save money by writing a smaller world. Timecrimes, for example, could be played on a stage with a small handful of actors. Cube (1997), in which unknown futuristic fugitives try to escape a deadly maze, is filmed almost entirely on a single, nondescript set.

2. Focus on the Writing

If you had a gigantic budget, you could make an enjoyable piece of entertainment even if your story were a piece of ... something else. But if you're making a shoestring film, you can't afford a bad story and two-dimensional characters because it'll never get past the screening committee. A good subtext can help a lot.

Habit (1996) plays vampirism as a metaphor for addiction. The need for human blood becomes something like an alcoholic's need for a drink. Perhaps one feels invincible when one become a vampire, as with the first time you try a powerful drug. But each fix gets you less and less high, and the withdrawal symptoms can kill you.

The implications of "out of sight, out of mind" in Science Fiction are both exciting and terrifying. Like alcohol, they amplify your natural personality. Having people forget you when you leave the room gives you the perfect opportunity to steal, insult, and abuse people you don't like. On the other hand, if you're naturally insecure, you're going to become a childish wreck when you realize nobody is ever going to love you longer than their next trip to the bathroom. Doing evil becomes incredibly easy; maintaining love becomes almost impossible.

In Timecrimes, the characters provide the subtext. The protagonist is a middle-aged Spaniard, well off, who pushes his way through the story like a bull, consequences and bystanders be damned. He's not entirely likeable, but he is entirely believable. Minority- and women's-studies professors could have a field day with the protagonist's recklessness and selfishness. Many time-travel films warn against tinkering with universal forces; this one's protagonist wants to know what the universe has done for him lately.

Primer's strong suit is the dialog. The two young inventors have heated discussions as they try to solve the problems in their almost-working time machine. They talk passionately and intensely in their own shorthand. The dialog is just technical enough that we can almost understand what they're saying. The screenwriter's best insight is to use pronouns, gestures, and slang to talk about the pieces that aren't quite working correctly, rather than using technobabble to try to explain the process to the audience.

3. Learn from The American Astronaut

A few movies go beyond good writing and a clever idea. Creative special effects, a sense of humor, or quirky characters can spice up your film even further. To incorporate these ideas, you might have to wear more than one hat, as did writer/director/composer Cory McAbee in The American Astronaut.

McAbee had a great idea for simulating low gravity on an asteroid. Shooting in slow motion gets you halfway there, but audiences know what slow-mo looks like, and it doesn't look like reduced gravity. McAbee had the idea to take short little skipping steps instead of normal-sized strides. Combined with high contrast night photography, slow motion, and a cheesy space helmet, the effect works unbelievably well.

McAbee is also a musician, and he incorporates several original rockabilly punk songs into the film. Sometimes the music backs a montage. In one scene it backs up a dance contest. There's even a surprisingly memorable theme song given how hard it is to sing. The film also has a dry, ironic sense of humor that puts the science fiction in the background. If The American Astronaut were a more earnest movie, the low-budget sci-fi components would be unconvincing and immature. But as a side dish to the humor and the quirkiness, the low-budget sci-fi ethos fits exactly right.

Even if you can't write music or film your own special effects, you can still write a good screenplay. Don't let armies of centaurs or bolts of pure energy intimidate you. Good science fiction can fit in any budget.