• Any vehicle from the Star Trek Universe: Dilithium Crystals. This is an element created just for Star Trek that powers everything from the U.S.S. Enterprise to a Klingon Bird of Prey. Dilithium had to be mined, just like we have to drill for oil, and could be hard to come by. Of course, when Star Trek: The Next Generation came out the writers decided to just cheat and make it something that they could make synthetically, thereby killing any future "we're out of gas!" storylines.
• The Time-Traveling Delorean from Back to the Future: plutonium, gas, and/or garbage. Doc Brown's time-tripping Delorean actually has an engine that does run on gas, although when he came back from the future he'd converted the flux capacitor to run on a Mr. Fusion device, thereby eliminating the need for plutonium pellets for driving through the decades. Just toss some trash inside, and you're good to go.
• Anything in the Battlestar Galactica universe: Tylium. In the world of BSG, both Cylon and Human ships run off of a fictional ore called tylium. It's only found on certain planets, and has to be mined, just like dilithium crystals. But unlike the crystals, it also has to be refined and turned into a gasoline like substance. No idea what kind of mileage you get out of it, but it also powers their "faster than light" drives, so it must pack quite a punch.
• The TARDIS from Doctor Who: artificial black holes, radiation, life force... take your pick. The TARDIS in the world of Doctor Who looks like a giant blue phonebooth, and travels through both time and space. However it's actually a sentient being that draws its power from one of several different sources, depending on what season of the show you're watching. In the current incarnation of the show, the Doctor has to stop periodically near a space-time rift and suck up the leaking radiation in order to keep things going. A sort of interstellar pit stop, if you will. Photo by lizardian.
• The Spaceship Heart of Gold from The Hitchhiker's Guide To The Galaxy: a cup of hot tea. The Heart of Gold ran on an infinite improbability drive that took it through "every point in the universe at once" when it was switched on. Not too shabby. All it took was an electronic brain and a good Brownian motion generator, like a cup of tea, and you're off. Probably the cheapest form of travel ever invented.
• Anything in Star Wars: your guess is as good as ours. While you sometimes see strange hoses and gizmos hooked to the ships before they launch, it was never made clear in these movies what they run on. George Lucas apparently never wanted us to get bored by the details, so you could fill in the blanks on your own for this one. Lando was running a gas-mining facility on Bespin in The Empire Strikes back, so maybe he was in the spaceship fuel business. We may never know, so be careful with whatever you put in the tank of your X-Wing.

• As always, extinguish all smoking materials while refueling and be sure to hold on to your receipts. Your own mileage may vary.

The Batmobile from Batman Begins. This was the first on-screen version of Batman's muscle car that didn't just look like a cheesy toy car. Instead of the stretched-out roadster of previous movies, director Christopher Nolan opted for a compact, tank-like design. In "attack mode" the driver shifts to the middle of the car, in a more secure prone position. This car doesn't look like it's only designed to impress Kim Basinger.
Top speed: 110 mph, plus jet engine and adjustable control surfaces let it jump 30 feet without a ramp.

The DeLorean from the Back To The Future movies. This car's main superpower is making those movies look incredibly dated. But it also travels in time if you feed it enough plutonium. And after a visit to the year 2015, it also gains the ability to fly, with wheels that turn sideways and become thrusters.
Top speed: A regular DeLorean could reach 124 mph. It needs to reach 88 mph to time-travel.

The flying taxi from The Fifth Element. It looks just like a regular cab, but it can fly. It handles amazingly well, judging from some of the teeny openings Bruce Willis manages to steer it through during the high-speed cop chase. And it can stop on a dime to hide behind billboards.
Top speed: Unclear, but it's fast. The original movie script says: "Korben and his flying taxi are absolute masters of the air. The cops have trouble following him."

The self-folding car from that SciFi Channel ad. Long after people have forgotten Flash Gordon and Tin Man, they'll still be passing around this ad. It looks like a regular pick-up truck, until the driver presses a button. Then it folds up to the size (and weight) of a golf ball.
Top speed: no clue.

The Whomobile on Doctor Who. Stranded on Earth in the early 1970s, the Doctor started dressing like Prince. Except instead of driving a little red Corvette, he pimped out an antique roadster named Bessie to go super fast. Then he built his own spaceship-looking car. With huge honking fins! Because, of course, an alien trapped on Earth has to stay incognito at all costs.
Top speed: 150 mph (in real life), plus the Whomobile can fly (using dodgy greenscreen.)

The Spinner from Blade Runner. Deckard's cop car flies, but also has vertical take-off and landing (VTOL). It uses regular internal combustion, plus antigrav and a jet engine. It also directs air downwards to create lift. And it has a pretty sweet glass cockpit.
Top speed: Deckard mentions a fellow cop was going 150 mph when he went off a cliff.

KITT, from the Knight Rider TV show and TV movies. KITT was a Pontiac Trans AM with a super-computer that could talk to Michael (its driver) and even drive itself. (Plus KITT prints money in one episode, which could be handy.) The new Knight Rider, airing in February, will feature a new KITT that can launch a mini-car drone and fire a rocket launcher
Top speed: 300 mph, plus a "turbo boost" lets you jump over obstacles.

The Lexus from Minority Report. Lexus designed a special flying car for Tom Cruise to zip around the city of 2054 in. The car includes an electric engine, body panels that change color at a voice command, doors and ignition that require a DNA match, and "auto valet."
Top speed: According to Lexus, this car can get up to about 350 mph. We have a winner!

Diamond Select Toys has created a replica of the famous gadget that "makes time travel possible" in some unexplained way that involves flashing lights. It's house in a replica box that looks just like the one in the film, and it can be sitting proudly in your living room next year. Better yet, just install this sucker in your Honda and see what happens when you get up to 88 miles per hour. Hopefully you'll see some serious shit.

Cool Stuff: Back To The Future Flux Capacitor Replica [/Film]