I don’t know how ‘unknown’ it is but The Apostle - with Robert Duvall as a gifted evangelist preacher on the run is excellent. You might rent that and Sling Blade and have yourself a Southern smalltown oddball movie fest.
Three movies, all starring the goddess Tuesday Weld:
Play it as it Lays
Pretty Poison
Lord Love a Duck
Just got this one on DVD last week!
A few others:
Panic in Year Zero – ultra-low-budget sf movie from early 1960s has Ray Milland and his family narrowly missing a nuclear attack on LA (the glass painting of LA under a mushroom cloud – cheap, but much better than the sloppy use of stock footage of atomic tests you usually see – is as exotic as the effects get) and trying to survive among the lawless crowd of refugees. Pretty good film with a Heinleinian feel to it. they have to overcome obstacles and solve problems --How do you cross a bumper-to-bumper road of cars filled with panicked refugees? – before they reach a safe haven. Dated, but worth seeing.
Kronos --1957 science fiction film about an invading alien robot tat lands in the sea, then makes its way to land to wreak havoc (I really think that the book The Iron Giant was based on owes quite a bit to this film). What distinguishes this film from the other 1950s monster-on-the-loose flicks is its style. The nearly featureless box box of a robot , propelling itself across the landscaope with three thumping legs and one rotating one is totally unlike any other, and the visual flair is fantastic – you’d never believe a featureless box could be so visually appealing and stylized, but it is. Done by a lot of the same folks that gave us Forbidden Planet. Unfortunately, it’s intellectually vapid, but it’s a joy to behold.
Creation of the Humanoids – incredibly obscure science fiction story starring nobody you ever heard of. The “Humanoids” are anthropomorphic robots that get progressively more human as they’re refined in a bleak future. Surprisingly mature and cerebral, with an Asimovian feel to it.
Enthusiastic seconds for Breaker Morant and The Emperor’s New Groove. Boy, I’ll bet that’s the first time in history that THOSE two films have ever been mentioned in the same sentence.
My recommendation: *A Midwinter’s Tale *. Also known as In The Bleak Midwinter, this film was Kenneth Branagh’s Christmas present to wannabe thespians everywhere. It’s the story of a down-on-his-luck actor (Michael Maloney) who decides to mount a low-budget production of Hamlet. As a Christmas show. In two weeks. With only seven actors. And this is supposed to save his sanity, somehow. The dialogue is delightfully witty and delivered in a spot-on, rapid-fire fashion by an enormously talented ensemble cast (featuring several of Branagh’s regulars). Still not available on DVD, sed dum spiro, spero.
Don’t forget The Incredibles, which has an invading (non-alien) robot that lands on a beach, then makes its way downtown to wreak havoc. Not only was the movie directed by Iron Giant’s Brad Bird, but the villian’s password was “KRONOS”. 
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Ah, Kronos ! One of my favorites! I can always count on you, Cal !
Two Western spoofs:
The Villain starring Kirk Douglas
Rustler’s Rhapsody with Tom Berenger
Not to be missed whether you love or hate Westerns!
How about “Barry McKenzie Holds His Own” directed by Bruce Beresford and written by Beresford and Barry (“Dame Edna”) Humphries? Stupid as a fried popsicle, but damned funny in a totally over the top, stereotypically Australian manner… Gotta love Donald Pleasance as a vampire, really you do…
I’ve always loved “The Madwoman of Chaillot” and can recommend it without reservation.
“Tapeheads” never got the recognition it deserved, snide, funny and a great soundtrack–the “Roscoe Rap” marks the first time I figured that rap music might not be just noise.