Akira
Caligula
Nearly any Terry Gilliam movie
Fear and Loathing in Las Vegas
Fargo
Ladies and Gentlemen…I give you:
The MOST bizarre movie I’ve ever seen. Weird, but funny.
some seconding of motions, but:
Santo Sangre
Man Bites Dog
Un Chien Andalou
Tetsuo: the Iron Man
if kink is ok, then Cafe Flesh
Day of the Locust
anything by the Brothers Quay (street of crocodiles, boy howdy!)
Svenkmayer-- Faust
the 500 Fingers of Doctor T (dr seuss meets bizarroland)
Ooh… I forgot:
The Whoopie Boys.
I have seen a lot of the movies on this list, and I would say that 2 stand out for me.
Holy Mountain by Jodorowski takes the concept of bizarness to a whole new level. It also features some truly amazing, even beautiful imagery (the conquest of Mexico performed by toads and lizards is really something no-one should miss), and despite it’s completely bonkers, almost non-existant plot, it alwas keeps you 100 % engaged.
My other pick would be Meet the Feebles. Tagline- “hell hath no fury like a hippo with a machine gun” This only hints at how deliciously weird, sick, twisted and hilarious this film is. Watch it.
Amen. I saw that movie during a freshmen year Philosophy course. I think my professor was trying to connect it to Max Weber and bureaucracy, but I’m still scratching my head.
Also, Mad Max Beyond Thunderdome. Perhaps it would have made more sense had I seen the first two, but I am not entirely convinced of this.
Motel Hell
Greaser’s Palace is very, very weird. Jesus in a zoot suit in the old west! A homosexual Herve Villechaize! Directed by Robert Downey, Sr.!
The Reflecting Skin is great, but I wouldn’t say it’s too bizarre.
Institute Benjamenta is a pretty strange film by the Brother’s Quay (those guys who made those weird puppet shorts on MTV in the early 90’s). Plus it’s got Alice Krige, a weird actress.
Breakfast of Champions is comprehensible if you’ve read the Vonnegut novel. Unfortunately it’s also completely stupid if you’ve read the Vonnegut novel. If you want to read a WTF? adaption of a Vonnegut novel, check out Slapstick (Of Another Kind), which is one of the worst movies I’ve ever seen.
The Dark Backward is a pretty strange movie. It star’s Judd Nelson as a wannabe stand up comic who grows a third arm out of his back. It also has Bill Paxton having sex with some extrememly fat ladies.
The Cook, the Thief, His Wife and Her Lover
Very bizzare but the ending makes the whole movie great.
Johnny Got His Gun. (1971)
Timothy Bottom stars as the most badly wounded soldier of the First World War in this weird adaptation of Dalton Trumbo’s famous anti-war novel. Bottom is an American soldier who has lost both of his arms, his legs, and his entire face. He spends most of the movie lying on his back with some kind of bag over his face in a military hospital. The army assumes he is a vegetable and is keeping him alive for experimental reasons. But in reality, Bottoms is fully conscious, only unable to communicate because he lacks eyes, a mouth, limbs and ears.
Reefer Madness. (1936)
The bulk of the film focuses on almost slapstick scenes of high school kids smoking pot and quickly going insane, playing “evil” jazz music, being committed, and going on a murder spree.
Baxter is another fun, yet wierd one. The tagline is “Beware the dog that thinks.” The whole film is done from the perspective of a dog and is narrated by him. Cute and cuddly? Nuh-uh. This is one creepy pup. You will definitely look at your house pets differently.
And, yeah, Meet the Feebles is a great party movie. Go Peter Jackson!
A Clockwork Orange. Watched it for the first time in years a few weeks ago. Totally bizarre.
“Manos; Hands of Fate” luckilly it only seems to be available in the MST3K’ed version
the only film made by a texas fertilizer salesman (Hal P. Warren) who was also the ?hero? of the film
The Frank Zappa-esque “Master”
Torgo, the “Master”'s monstrous servant, who you know he’s a monster because he has…
BIG KNEES! (and an annoying theme song consisting of 4 notes repeated ad-infinitum)
The Master’s wives, who are kept in stasis, until they are needed to wrestle while wearing diaphonous gowns (probably the reason this “movie” was made)
even with the assistance of Joel and the Bots, it’s almost unwatchable, bad enough to cause brain aneurysms
Thrill! to the horrible, muffled MONO sound and “music”
Chills! caused by shooting the film with an 8MM Bell& Howell movie camera that could only record 30 seconds at a time without sound, forcing all the dialog to be added in post-“production” (Hal apparently did almost all of the male voices in the film)
Feel! your brain turn to mush, even with the insulating safety of Joel and the Bots
you have no idea what a bad film is, until you’ve had the (mis)fortune to see Manos!
read it if you dare… 
Realized i missed the Halloween deadline, but my vote would be Gummo. Reminiscent of Larry Clark movies, but more disturbing in every detail. If Requim for a Dream disturbs you so will Gummo.