I believe that would be The Arrival. I actually had the “privilege” of reading the original screenplay called something like Holocaust or Fallout or something like that. Even then, I could tell that this one would be a total dog.
Already mentioned so far, Freddy Got Fingered, Battlefield Earth.
My additions for movies where the end result is really crappy considering the resources that went into them:
** Robin Hood: Men in Tights**. This POS taints everything Mel Brooks ever did.
** The Art of War **. I usually like Wesley Snipes, but I left the theater on this one.
** A Life Less Ordinary** It’s got Cameron Diaz waltzing around in her underwear, and it is still barely watchable
And one B-film that is bad on so many levels:
** KISS Meets the Phantom of the Park**. Even more painful than you’d think.
Johnny Mnemonic .
Have to disagree about this – not about Supergirl being bad – that’s a given – but about the series being at a peak. The Superman series peaked with the very first Richard Donner-directed, star-studded, John Williams-scored film. They decreased in quality in geometric progression after that, with Superman II being better than your average sequel quality, Superman III being abysmal, **Supergirl ** being amazingly abysmal, and Superman IV starting to scrape the bottom of the barrel (despite the return of regulars from the first film). A pretty good roundup of the shortcomings of these films is currently abvailable at www.jabootu.com and its associated “B-movie Comic Book Movie Cabal for May”.
Random Hearts.
Apparently no one here’s heard of a film called “Loser.” Not the teen movie from last year or so, but some earlier film by that name which I found on video.
The characters are some post-high-school kids trying to make it in L.A./Hollywood, and about the only the only thing I remember is that the main character breaks the glasses of his roommate, a fat guy who liked to paint miniature Nazi soldiers and who was easily bullied into spending tons of money on expensive liquor in a vain attempt to be part of the crowd, and that roommate ends up dying. The characters have no redeeming personal traits, the acting was more wooden than Pinocchio, the movie had no plot…I couldn’t even tell you who “acted” in it, they were a bunch of no-names.
Lord, that film was awful.
I also really hated Four Weddings and a Funeral, but clearly that will not rank up with some of the stinkers listed in this thread. I just thought I’d put the name out there.
Sexy Beast - Awful and painful to watch?
Any movie with Tom Green/Pauli Shore in it.
Trash from the Andy Warhol Factory, 1970. Surprised the hell out of me that it got 6.8/10 on the IMDB user rating system. Those lucky Finns never had to see it - it was banned in Finland.
Worst ever was that POS released in 1996 starring Helen Hunt and Bill Paxton…you all know it, but I sure didn’t love it…
TWISTER.
Only movie I have ever left the theater for.
Movies I found unbearable (and I have pretty low standards):
Myra Breckenridge
Beyond the Valley of the Dolls
EdTV
First Kid (forced to see this with younger siblings)
The Mummy Returns
The Horse Whisperer is not only the worst movie ever made; it is the worst thing of any sort, ever.
Road House was bad, but Stone Cold was worse. It starred ex-linebacker Brian Bosworth. Apparently he felt that his trademark bleached mohawk qualified him to be an action movie star. As a form of karmic punishment, he later became a commentator for the XFL.
As for MST3K movies, The Wild Wild World of Batwoman is right up there. A poor attempt at camp and a successful attempt at misogyny. Plus, they actually spliced enitre scenes from a Mexican wresling movie.
Helen Hunt… tight, white shirt… raining all the time… Helen always outdoors…
You left? 
Are you serious?
Apparently no one has seen the Crow 4. Or maybe it was 3, I don’t know. All I know is that I asked my mom to rent The Crow, and she brought this piece of crap home. It has that girl from Interview with the Vampire in it (Kirsten Dunst?), and since she actually took the part, I’d assume her career went downhill right after IwtV.
Got another one:
Phantasm 4. I watched an hour into this tripe and couldn’t make the least bit of sense out of it.
As soon as I saw the thread title the name Cable guy fell out of my mouth. Sooo bad. The ironic thing is my husband is a cable guy. 
I loved Dude, Where’s my Car? . And I’m not a teenager.
Okay, I can now safely say that I have seen the Worst. Movie. Ever. Anyone else watching SciFi last night?
Blood Surf.
Oh. My. Freakin’. Gawd. It’s Jaws with a horrific script, eye-gouging acting, and a 31-foot salt water croc that can apparently launch itself a good 40 feet vertically out of the water.
Did any of the other TMs know that salt water crocs will positively refuse to go into fresh water, even if dinner is sitting less than 20 feet away? It must be true…
Augh.
-BK
I’d agree with all votes for Armageddon - complete drivel
But I’d have to go with 3000 Miles to Graceland as probably the worst I can remember. It had a good cast (Costner, Kurt Russell, Courtney Cox, David Arquestte, Christian Slater) but was utterly incomprehensible. The movie ended about 1/2 way through and they tacked on about 5 endings, one after the other. About as much fun as a root canal!
lo171
I liked this one, but to each his own.
Blast From the Past. TMR reminded me of this Brenden Frasier stinker. He is just very annoying.
Oo! It was on the movie channel one day, and I thought to myself “I think I’ll watch this to see if it really, truly is as bad as they say…”
Oh, it was! It really, really was as awful as they say…
I wann a watch Supernova to find out if it really is as awful as they say too.
Movie I hated the most? The People Under the Stairs. Made me grind my teeth.