Big Trouble in Little China is a ludicrous movie, but I LOVE, LOVE, LOVE it.
Came in here to mention this one. It’s one of the few movies that I’ve upgraded to Blu-Ray (and upgraded a few years before from LD to DVD). The Blu is a grain-fest, but it was worth it. Still haven’t seen the remake.
The Last Boy Scout. It’s as if the film makers looked at Lethal Weapon and Die Hard, made a list of what they thought made those movies work, then proceeded to guess wrong on every item on their list. A bad, bad movie, and I love it.
+1
Assuming you mean the 1960s version with David Niven as “Sir James Bond”, and not the 1950s TV adaptation.
Howard The Duck.
I think they have a medication you can take for that now. 
It’s a stupid Stephen Segal movie (is that redundant?) But it is totally worth it for a couple of things.
First, Segal’s bad-ass Navy Seal has been demoted to a cook. But the script understands that the only way you become a bad-ass Navy Seal one-man killing machine in the first place is by taking your job very seriously. So he’s a cook, and he takes the job of being a cook very seriously. So when he gets locked in the cooler by the bad guys, he shouts “Get my pies out of the oven!”.
Second, Tommy Lee Jones not just chewing the scenery but Fletcherizing it.
Third, Erika Eleniak’s nude scene popping out of the cake. And not just to obey the Rule of Three.
I’ll see your Under Siege and raise you Commando.
That was surprisingly entertaining. Are any of Ed Wood’s other movies watchable?
Predator and all four Rambo movies. Full House! 
Well, they’re all on about the same level, that’s for sure! :rolleyes:
I don’t think Plan 9 is the kind of movie the OP was referring to. Otherwise someone would have mentioned Billy the Kid vs. Dracula and They Saved Hitler’s Brain by now. 
I love Under Seige and Van Helsing too! And Monday night I’m going to the Music Box Theater, and pay cold hard cash ($5), of my own free will, to see Ishtar on the big screen. I haven’t seen it since it was first released but I remember liking it and thinking it was very funny then. It was only after seeing it that I heard how bad it was supposed to be and anyway, everyone should hate it because it went over budget and that’s such a crime.
Deuce Bigalow, Male Gigolo. The entire movie is a walking cliche with old, tired jokes, but I can’t get enough of it.
The entire genre of teen hip hop dance off movies. Y’know, the Step Up franchise, Save the Last Dance, etc. There are some pretty insane athletics going on, and I always want to go ahead and exercise after watching. 
Okay, I’ll admit it, I can still get suckered into a melodramatic teen romance too.
Magic Mike. I’m a heterosexual female.
Boogie Nights. I can’t stop analyzing the back story of each character.
Several of the movies already mentioned so I’ll add:
Waterworld. People tell me I’m not supposed to like it but I’ll watch it whenever it comes on.
Battlefield Earth. Same as above.
Armageddon.
Both of these films have very good to excellent reputations; Boogle Nights even received several Academy Award nominations, and both received nominations or awards from various groups.
Xanadu.
Yeah, I hate it when they review the budget. It’s not like I spent $100,000,000 to see it. On the other hand, I recall it looking like it was shot on a back lot.
The Boat That Rocked (or Pirate Radio) was none to good – cliched and formulaic – but I still enjoy it. Got the European version from my cousin, the one with the “electric ladyland” scene that was left out of the US release.
A Life Less Ordinary was pretty dumb, but I still like it quite a lot.