Killer Klowns from Outer Space
Big Trouble in Little China
They Live
Some of my favourites:
The Big Lebowski
Kung Pow: Enter The Fist
Hercules Returns
Trainspotting
Lock, Stock, & Two Smoking Barrels
Are we including Hong Kong cinema in here? Because if we are, I’ll add A Better Tomorrow II, Vengeance, and Kung Fu Hustle to the list as well.
Lisztomania with Roger Daltrey is my somewhat obscure favorite. Once seen, it is never forgotten. A demonic Richard Wagner creats a Hitler Frankenstein which Daltrey as Franz Liszt destroys with a pipe organ fighter jet that uses showgirls as ammunition. Oh, and Ringo Starr shows up as the Pope. I love it.
I suspect I’m one of a very few who enjoys simply watching and listening to Rocky Horror Picture Show. The audience activity in a theatre would ruin my enjoyment of the movie.
While I enjoyed Kentucky Fried Movie, Amazon Women on the Moon was better.
Dunno if these count as cult except in my mind, but they’re relatively unknown and enjoyable movies:
The King of Comedy
State and Main
Dead Men Don’t Wear Plaid
Mostly from my rental queue over the last few years:
Destry Rides Again
The Barbarian Invasions
The Lives of Others
Being There
Man From Earth
Harvey
The City of Lost Children
Proof (1991)
Delicatessen
Thank You for Smoking
Old Gringo
Gods and Monsters
A Bucket of Blood
The Forbidden Zone
Spider Baby
Freaks
Eating Raoul
Betty Blue (the theatrical cut)
Tromeo and Juliet
Ooh, good one.
The Adventures of Buckaroo Banzai Across the Eighth Dimension!
Dune
Ferocious Female Freedom Fighters
True Stories
Frankenhooker
How could I have forgotten that one?
(Actually, there are others on my shelves that I should have listed; but I didn’t look for them.)
Sid and Nancy
Pulp Fiction
Duel
The Big Lebowski
They Live
Boon Dog Saints
Good Fellas
The Shining
Fargo
Idiocracy
Pretty In Pink
The Goonies
Tommy Boy
Get Crazy.
Not available on DVD, but I got a good VHS copy on Ebay. I had to buy two copies, as the first one had corrupted sound. Others may not see the greatness and refuse to reissue it, but I’ve got mine! 
Do you mean The Boondock Saints?
Ever heard of The Blue Iguana and The Blood of Heroes?
Bryan-Bob says check 'em out.
I liked The Blue Iguana too.
Percival, I’m not certain that well-known, commercially successful movies such as Pulp Fiction count as cult movies.
Nevertheless, Pulp Fiction does have a following.
Kalifornia
Freaks
Kaspar Hauser (Werner Herzog version)
Wild at Heart
The Atomic Cafe
The Bridge
Brother’s Keeper
Cocaine Cowboys
The Lives of Others
Grey Gardens (original)
The Natural History of the Chicken (I have the DVD–but I saw this was on PBS last week!)
Hands on a Hard Body
The Story of the Weeping Camel
Downfall (Der Untergang)
Nosferatu (original)
Little Dieter Must Fly
Paradise Lost (films 1 & 2)
The Station Agent
Plagues & Pleasures on the Salton Sea
Dammit, I’m weird!! :eek:
Leningrad Cowboys Go America
So does Gone with the Wind, and In the Heat of the Night. But they’re classics, not cult, as is Pulp Fiction. Different thread, maybe? 
The structure of Pulp Fiction is significantly different from GWTW. I’m not claiming it is a ‘cult film’, but I can see how some would consider it one. Quentin Tarantino is a bit of a quirky filmmaker. I don’t think that Pulp Fiction or Reservoir Dogs should be excluded just because they were commercially successful.
YMMV.
Seconds on Schizopolis - I have a copy on VHS, everyone I have shown it to is seeing it for the first time. I don’t think anyone saw it when it came out, it rules.
Thirds on Eating Raoul and seconds on Rock n Roll High School - heck anything with Paul Bartel and Mary Woronov in it is usually good for a weird hour and a half. He directed Eating Raoul, and Deathrace 2000. I just saw that he died back in 2000. Dang, well, at leas the year was apropos.
And to the ones above, I’ll add:
Tetsuo: The Iron Man
Naked Lunch
Man Bites Dog
What’s Up, Tiger Lily?