I've read some fics that were just ridiculous (plus I've written some fics that are just ridiculous) so ff.net is the best bet.
For instance, I read this Yu-Gi-Oh! fanfic series that's basically about a blind Christian morbid orphan with a big bad balance of doom and the adventures of the POS... I mean POF.
I'm also in the middle of writing a pathetic-looking Gundam series that basically takes elements from other Gundam series and brings them together to form a pathetic lot.
Well anyway, if you want to look for bad work, then ff.net is a good choice. The old work is especially good fodder so look around.