When I think of stupid movies, I think of the overhyped vapid shit Hollywood puts out. If you want campy trashy movies, any John Waters flick
before Cecil B Demented is worth a 1000 laughs. They are on the sleazy side and gross but thats what makes it fun. John Waters made Edy the Egg Lady, and Divine stars. Sadly both are no longer with us.
Also I feel Larry The Cable Guy seems to be stupid funny.
Also, from 1965 or 1966 The Loved Ones
starring Rod Steiger.
See you in the aisles.