I like all the Jerry Lewis and Dean Martin movies.
The Nutty Professor, *edit: the original!* which is a very superior bad movie.
All the Maria Montez & Jon Hall movies from the 1940's...very, very bad, but wonderful.
Don't Bother To Knock...a bad movie with Marilyn Monroe...which makes it even better.
There are many 1950's crime and juvenile delinquent dramas which are spectacularly bad, but I cannot name a single one right now.
The Rocky Horror Picture Show...which when viewed by the light of day is just, well, inescapably bad.
All the John Waters movies, but I have a particular fondness for Polyester because I saw it in the theater when I was 16...complete with
Odorama!
Freaks, Carnival of Souls, Night of the Living Dead....come on, don't give me that psychological rigamarole they're bad.
What About Bob? It's really bad...but Bill Murray is so frigging adorable.
rb, I didn't care much for Napoleon Dynamite (perhaps I should give it another chance) but I LOVED Welcome to the Dollhouse...I haven't thought of that one in a couple of years and I need to watch it again...thanks for reminding me.