Though it may have been mentioned somewhere in the last 6 or 7 pages (I didn't read the whole thread), I think
Brain Dead (or Dead Alive in the US) certainly deserves a mention here.
While it might not actually properly be categorized as a "Bad Film" (personally I think it's a work of genius), it is probably categorized as such by most movie snobs. That said, for anyone who hasn't watched it, do so at your earliest convenience. You
will be entertained. It is one of the funniest movies I've ever seen, and it is actually intentionally funny. Combined with Bad Taste, it does make you wonder which movie exec at New Line Cinema looked at Peter Jackson's past productions and decided to throw untold millions of dollars at him in order to make Lord of the Rings. I'm glad he did, but I've never understood the decision.