Evil Dead
Evil Dead 2
Army of Darkness
Rocky Horror Picture Show
Mars Attacks
Top Gun

The original "Willard" from the 70's is pretty good.
Now and forever "UHF"

Rocky Horror Picture Show and Kentucky Fried Movie are good examples.

I also feel that in the fullness of time, Lone Star State of Mind as well as Super Troopers will achieve this exalted status. Besides, I'm hot for "Baby."

All I have to say is: Six String Samurai

Alternate history where the bomb dropped and world is a wasteland except 'Lost Vegas' where Elvis has been crowned king? CHECK

Buddy Holly traveling the wastes with a six string guitar and a katana fighting off scavangers, a bowling team turned assasins, and the invading Russian army so that he can claim his place on the now dead Elvis' throne as the new king of rock and rolla? CHECK

Death and his minions personified as a black tophat wearing metal band? CHECK

Bad-ass true rock and roll soundtrack? CHECK

"Now bow before the might of heavy metal!" - Death

I'm gonna second Hedwig and the Angry Inch, although I don't know if it's old enough to be a "cult classic" yet. But, it does get the same audience participation and shadow actors that you see at RHPS screenings.

I'm also going to have to disagree with a lot of the nominations here. If the movie was released in the past five years, it certainly can't be considered a "classic" yet. (Thus my reservations about Hedwig). And, if the movie was released in mainstream theaters with mostly mainstream actors (Old School, Ferris Bueller's Day Off, Office Space, etc.), it can't be cult.

Mine're:

Donnie Darko
Do The Right Thing
The Evil Dead movies
Incubus
Office Space, though I doubt it's really considered "cult"
Breakfast Club
Fast Times at Ridgemont High
12 Monkies
Pi

They Live is a favorite of mine. that fight scene never ends!

they've probably already been mentioned, but in case they haven't, i'd throw in peter jackson's pre-LotR movies in the mix, particularly Meet the Feebles, Bad Taste and Dead Alive.

It's been said a couple times already, but these are my all-time Cult favs.

i think anything with Bruce Campbell in it would qualify as a cult classic (and, in my opinion, worth watching), particularly if it was directed by Sam Raimi.

oh, wait... i may have to take that back. he did have a cameo in at least one of the Spider-Man flicks, didn't he?

anyway, just voicing my agreement with the fact that the ED flicks rock! :D

Eraserhead....Best.....Cult......Movie......Ever.

Also don't forget el Topo, Holy Mountain,And Santa Sangre. Alejandro Jodorwsky rocks.

What a great list of movies. Cool, I've got to check out a few of these I missed.

Boondock Saints
Desperado
Army of Darkness (I have the t-shirt)
Princess Bride
Blues Brothers (fav. movie of all time)
Breakfast Club

I don't consider half of these movies as "cult classics", as they have become so cool that they're now mainstream.

However, some favorites of mine are Blood of Heroes, Master of the Flying Guillotine (best martial arts movie EVER), and Final Countdown. :D

The Wicker Man
Bitter Moon (disturbing)
Blue Velvet (and any other Davis Lynch film for that matter)
A Boy and His Dog
Reefer Madness
Altered States
Motorama
Zardoz

My all time fave, The Lair of the White Worm (one Hugh Grant doesn't put on him resume

A Clockwork Orange is brillant. Stanley Kubrick is a genius.

Meet the Feebles. And how about:

Man With The Screaming Brain?

And before LOTR
Braindead
Bad Taste (a very well named flick, indeed!)
(along with) Meet the Feebles

And another that should be a cult classic, imo
The Secret Adventures of Tom Thumb

Bad Taste is an awesome early Peter Jackson movie!

Also his other one which is better is Dead Alive. Real Classics! :D