Transformers Revenge of the Fallen is probably the worst movie ever made with a +100 million budget.
It's not that it's a failure on one level which can already wreck a movie. It's a failure on every single level a movie consits of, writing, acting, scene composition, editing, special effects, color grading, sound design, music... Absolutely nothing works which makes it quite of an achivement. No doubt there're worse films out there but I doubt any of them operate on such a grand, budget enabled scale of awfulness.
I actually recommended it to a lot of people so they learn to tell a simply mediocre movie from a truely terrible one.