Just watched one on Netflix called Good for Nothing. A very bad outlaw shoots up a bar and kidnaps a woman, but when he tries to rape her, he, uh, can’t perform. So about the first 3rd of the movie is him galloping around, carrying her along, looking for doctors with a cure for erectile dysfunction. It may also be the movie with the least dialog I’ve ever seen.
Strange as it was, I ended up liking it a lot and gave it 4 stars. What ya got to beat that?
One of my favorite westerns is The Oxbow Incident. It wasn’t that it was strange, but it’s a very dark, almost noir-ish film about mob violence, with Henry Fonda doing the honors.
Then there’s Ravenous, wherein frontier soldiers are eating human flesh. Technically, it’s a thriller, but takes place on the western frontier.
Hang 'em High, starring Clint Eastwood, starts with the lynching of the main character. I don’t remember most of the details, but I remember it as being not your typical Clint Eastwood movie.
El lTopo. The only things I remember about this movie are the naked boy from the first act, and there being alot of dwarves.
Probably not what you had in mind, but I’ll suggest Westworld.
The Terror Of Tiny Town. Musical with an all-midget cast. Mounted on Shetland ponies.
Sukiyaki Western Django is stylishly weird, although the plot is pretty straight-forward.
Bunraku is one of my favorite movies of the last decade. It’s about a gunman looking for revenge who teams up with a samurai to defeat The Woodman, a gang leader who controls the area. It’s filled with crazy awesome fights and some of the best lighting, sets and editing in recent memory. Truly awesome production design plus clown cars and ninjas!
The Good, the Bad, the Weird is about a couple of bounty hunters trying to get to a treasure map (and the treasure) while being pursued by bandits and the Japanese Army in Manchuria. It breaks down a bit in the 3rd act, but it’s still a lot of fun.
Then there’s The Valley of Gwangi which is about a cowboy who captures a T. Rex in the Forbidden Valley and then puts it on display in a Mexican Circus. I was a big fan of Ray Harryhausen as a kid, and he did the special effects. The first time I saw this was on a Saturday morning on WPIX and I remember loving the hell out of it.
But surely the weirdest western ever was Jodorowsky’s El Topo.
ETA: Dammit! Ninja’d by alphaboi! I’m trying to watch the Syracuse-Michigan game and can only type during commercial breaks! <shakes fist>
Featuring a Quentin Tarantino cameo where he speaks in a very, very odd accent.
You know, it’s technically modern “neo-western,” but it’s Peckinpah, dammit: Bring Me the Head of Alfredo Garcia.
I know it’s not technically a Western, but I figured for the purposes of this thread, it was a good fit. And yeah, by “straight-forward” I meant “a story we’ve seen before dozens of times”.
Also, Tarantino is easily the worst part of the movie. Most of the time I think he’s okay onscreen, but this was just gratuitous and superfluous and stinkerific.
Clint Eastwood’s High Plains Drifter is pretty fucking weird.
How about The Three Burials of Melquiades Estrada? Good movie; kinda weird.
Johnny Guitar: Nicholas Ray-directed effort that turns most western conventions on their head; Joan Crawford and Mercedes McCambridge play roles that in most other flicks would be the rancher patriarchs fighting over land, while Sterling Hayden and Scott Brady square off as Crawford’s former and current boy toys. Mighty racy stuff for the mid-fifties.
Zachariah: a bit hard to find, it’s a hippie-era headtrip featuring onscreen performances by The James Gang, Doug Kershaw, and the New York Rock and Roll Ensemble, with a screenplay by the Firesign Theatre, no less.
I remember a very curious western with a samurai and Charles Bronson..
Found it.
Red Sun (1971)
starring Charles Bronson, Ursula Andress, Toshirô Mifune, Alain Delon, Capucine
Back to the Future III 
SFC Schwartz
I think Jim Jarmusch’s Dead Man is a pretty strange western.
Greaser’s Palace. Just try to beat that one.
I don’t think it’s possible to top El Topo for weirdest Western.
Calamity Trail, by Dan Parkinson, is…sort of hard to describe. Surreal slapstick dressed in Western clothing, with a twist of fantasy, maybe.
It’s about a gentle, intelligent young artist from Boston whose tiniest actions often trigger cascades of bizarre, disastrous events. He’s sent away from Boston for his own safety after one of these mini-cataclysms. He sets out for the West to make his fortune, because he’s heard that’s where you go to do such things, and he needs a fortune to marry the beautiful girl he met at the train station.
Along the way, he’s threatened and/or pursued by gunslingers, hillbillies, marshals, thugs, assassins, crooked businessmen, a land drummer, Indian art critics, a guy with a giant gear on his foot, and an accidental octagenarian outlaw who’s trying to avert a prophecy. (Okay, maybe the accidental outlaw isn’t actually 80+, but she’s pretty old.)
I would love to see a movie made of it, but I don’t know if you could possibly do it justice. You’d have to leave out too many funny scenes and subplots. Maybe a miniseries would work.
Some damned zombie western I watched on streaming Netflix probably 3 years back. Hm, let me check netflix for the title. Ha, Undead or Alive. Geronimo put a curse on white men so that when they die they come back as zombies, and this sort of odd couple of cowboys steals something [?] and goes on the run, meets up with a pretty indian woman and are chased all over by zombie cavalry and words finally escape me. Watch it, it is really fun for a get slightly drunk and eat wings and other pub grub sort of film marathon.