Stabwound fucking is one that comes to mind. It really doesn't get much more violent than that. I always wanted to put people through garbage disposals and roll them in salt when I was angry, myself, though.
It's only sick if you actually do it. Blood grosses me out and so I'd never actually do it. Just draw pictures of stick guys doing it.
Ooooh. That's horrible. Haha. But, the thing about it is I think that would be more psychological than physical, I don't think eyes have that many nerves.