I've never seen any of the Twilight movies, so they won't be listed, but hm... I've seen a number of movies I thought were incredibly pointless and stupid.
Robin Hood: Men in Tights
Monty Python and the Holy Grail
Superbad
The Hangover
All movies I'd rather watch grass grow than see again.
but the most hilariously bad movie ive seen is GI Joes
I think Santa Claus Conquers the Martians is one of the worst movies I've seen, although I found it humorous nonetheless.