Blood Rayne - it was so hilariously bad that it was almost enjoyable.
The Expendables - Such a waste of money. It is basically one big action hero circle jerk with all of the violence of big action movies, without any of the entertaining plot or funny quirks that other action movies have. I LOVE Arnie movies, but the plots are actually semi-interesting, and his one-liners are amazing. Expendables doesn't have anything like that, it is just garbage.
Ghost Rider: Spirit of Vengeance - So. Fucking. Bad.
And I'll include Bridge to Terabithia because that movie made me so fucking sad... Its really good, but I don't suggest anyone watch it because of how sad it made me.