This week sees the release of "Paul," Simon Pegg & Nick Frost's outrageous comic road movie where they play two British sci-fi nerds in America who help a rowdy alien (Seth Rogen) get back to his home planet. Over the course of their journey they inevitably get their minds blown in many ways, although Paul's love of super-strong Mary Jane is definitely involved at one point.

Since Jack Kerouac first put pedal to the literary metal, the horizon-expanding aspect of a road trip seems intrinsically linked with a factor of trippiness, and thus we chose the nine greatest movies that indulge in a bizarre, crazy, and surreal atmosphere. Dig it, man!

9. 'The Hangover' (2009)

The equation is simple: 4 dudes + a night of extreme Vegas boozing = 3 dudes. When the self-proclaimed Wolf Pack of four guys celebrating their friend's bachelor party cannot recall the debauchery of the night before, and wake up to a hotel room filled with odd artifacts of their Sin City fun (a baby, a hospital bracelet, tiger, etc), they have to pull together what little is left of their braincells to find the groom before he's late to the altar. Todd Phillips took a trio of talented but less-than-household names (Bradley Cooper, Ed Helms, Zach Galifianakis) and made the most-successful R-rated comedy of all time, with a little punching up from Mike Tyson. Iron Mike doesn't like to lose.

Under the influence of: Alcohol & Roofies

Trippiest Moment: Tiger in the bathroom.

8. 'Mad Max Beyond Thunderdome' (1985)

George Miller's previous two chapters in his Mad Max oeuvre were already pretty nuts, a strange amalgam of American International biker gang movies, Akira Kurosawa samurai films, and Joseph Campbell hero mythology, mixed with S&M leather and an Outback flavor. This third entry in the trilogy gave a nitro-boost to weirdness, though, with next-level stuff like a barter city powered by pig excrement, Tina Turner's wiggity-whack hairstyle, and a gravity-defying battle to-the-death with a down syndrome giant inside the title arena. Mel Gibson's rugged intensity is personified in this, his most iconic character, and now that we're living in the era of CGI cars and "digital doubles," it's refreshing to see old school car chases with real blokes risking their bollocks for our amusement.

Under the influence of: Gasoline

Trippiest Moment: Mel Gibson snags a midget from Tina Turner on a moving train.

7. 'Wristcutters: A Love Story' (2006)

After unceremoniously offing himself, Zia (nearly famous "Almost Famous" star Patrick Fugit) finds himself trapped in a limboland populated entirely with suicides. The world is strange only for how utterly mundanely alike it is to our own, except that no one can smile and if you shot yourself on Earth you may still have a bullet hole in your head kinda deal. When Zia discovers his girlfriend (Leslie Bibb) took her own life shortly after he did, he sets off on a cross-country… er, cross-purgatory road trip to find her. With his edgy Russian rocker friend Eugene (Shea Whigham) and a pixie-ish hitchhiker (Shannyn Sossamon), they encounter a strange cult of miracle worshippers led by none other than Tom Waits.

Under the influence of: Antidepressants

Trippiest Moment: A vortex to another dimension is discovered under the passenger-side seat.

6. 'Natural Born Killers' (1994)

Oliver Stone's ultraviolent indictment of mass-media brainwashing concerns two homicidal psychopaths named Mickey (Woody Harrelson) and Mallory (Juliette Lewis), who set off on a love-soaked kill rampage across America. These latter-day Starkweathers clearly get off on the murders they commit, but it's the tabloid-obsessed audiences who are truly mesmerized. Stone uses lens filters, special effects, Dutch angles, black & white, animation, sitcom laughtracks, archival TV footage, and just about every experimental film technique you could think of to alternately take you inside the killers' heads then back out again into the media circus around them. If that sounds like the most paranoid amusement park ride of all time, that's because it is.

Under the influence of: Peyote

Trippiest Moment: Mickey & Mallory's blood turns into red animated snakes.

5. 'Pee-Wee's Big Adventure' (1985)

Paul Reubens is currently creating a whole new generation of fans through the resurrection of his most famous character, Pee Wee Herman, the wackiest manchild who ever was. Back in the day he won over Gen Xers and their parents alike through this crazypants road movie in which Pee Wee travels the country looking for his beloved bicycle. Tim Burton made his directorial debut, and he and Reubens' sensibilities go together like peanut butter and jellybeans (meaning deliciously). Playing like a live-action cartoon, the movie has everything from biker gangs to evil clowns to escaped convicts to Godzilla; just remember to steer clear of the basement if you visit The Alamo.

Under the influence of: Mr. T Cereal

Trippiest Moment: Large Marge.

4. 'Easy Rider' (1969)

Dennis Hopper and Peter Fonda rode their choppers into movie history and literally reshaped the cinematic landscape with this ode to freedom and irresponsibility. The born-to-be-wild duo of Billy and Captain America score a huge drug deal (cameo by legendary music producer & convicted murderer Phil Spector!) and take a magic Harley ride through a hippie commune, jail, Louisiana, and hillbilly country. Even though they "blew it, man" in a spiritual sense, they managed to make Jack Nicholson a star, open the floodgates for a wave of youth-oriented/director-controlled films, and define a generation. You dig?

Under the influence of: Cocaine & Marijuana & LSD & Dennis Hopper

Trippiest Moment: Mardi Gras cemetery freak out.

3. 'Zombieland' (2009)

The second entry on our list of triptastic films to feature Woody Harrelson. Coincidence? We think not. With the planet engulfed in an apocalyptic zombie epidemic, the High Times poster boy hit the road with unlikely companion Jesse Eisenberg on a quest to find a certain cream-filled Hostess treat, kicking all manner of undead ass along the way. The chemistry between Harrelson's whiskey guzzlin', uzi totin' good ol' boy and Eisenberg's twitching powderkeg of neurosis melds perfectly, appropriate since the movie's tone exists somewhere between Woody Allen and Bruce Campbell. Sequel, please!

Under the influence of: Twinkies & Mountain Dew Code Red

Trippiest Moment: Super-slow-mo opening credits.

2. 'Fear and Loathing in Las Vegas' (1998)

Hunter S. Thompson's freewheeling tome for the death of the American Dream had proved "unfilmmable" for decades after powerhouses like Martin Scorsese, Ralph Bakshi, and Oliver Stone couldn't get it off the ground. It took a top-shelf lunatic like director Terry Gilliam ("Brazil") to bring this hilarious, frequently terrifying work of pseudo-fiction to life, and an equally certifiable star named Johnny Depp to go balls-out in his portrayal of the author, aka Raoul Duke. In 1971, Duke and his possibly-Samoan attorney Dr. Gonzo (Benicio del Toro) drive through Bat Country to Las Vegas, their trunk packed with goodies, and experience some super-distorted reality, including but not limited to a desk clerk whose head turns into a Moray eel, Satan growing boobs on his back, and LSD trips in the bathroom with Flea.

Under the influence of: Every type of drug known to civilized man since 1544 A.D.

Trippiest Moment: The whole film.

1. 'The Wizard of Oz' (1939)

Yes, the "most watched motion picture in history" is also our most psychedelic. Far out, man. Dorothy's coma fantasy showcases a candy-colored land of cowardly lions, brainless scarecrows, heartless tin men, and a bunch of singing little people with a really bad union. Because it's important to teach children that ugly people are evil and pretty people are good, there are corresponding witches for said moral lesson. In defense of the Wicked Witch of the West, you'd be kinda peeved too if your skin had been bleached green in some apparent Land of Oz Nuclear Power Plant disaster. Cue up "Dark Side of the Moon" and let this movie whisk you down the Yellow Brick Road, and although skipping and singing towards your destination is great cardio, we recommend the Emerald City Commuter Bus for the trip back.

Under the influence of: Magic Mushrooms, possibly Crack & PCP

Trippiest Moment: FLYING MONKEYS!