Donnie Darko... don't watch that if you're feeling mentally exhausted -- it's a good movie, but you'll need your thinking hat on. Not something to watch if you just want some mindless entertainment (I guess that's more like what Michael Bay excels in ).

There's also "Devil" by M. Night Shyamalan (checks Google - yes, I spelt it right! ) - the same director as the Sixth Sense. Apparently that's going to be the first in a series (trilogy?) he's working on.