Haibane Renmei? SP1 did an awesome lesson plan for his Sunday School class
here.
Trigun is also pretty good. Mind if I share a quick personal story?
I was a very suicidal teenager, but I'm not going into the details regarding the "why". I kept a rope by my bed at all times, thinking that one day I'd hang myself in the woods outside. I was shuffled from psychologist to psychologist (they inspired me to be a psychology major, but I left after turning antipsychiatry - go figure, I doubt that they'll graduate someone who rejects the notion of mental illness), I would collapse in a fit of exhaustion after long prayers, for they were the only things to keep me from going over the edge; and I finally did attempt suicide when I was 17.
Believe it or not,
Trigun was my first real introduction to grace, as our church was in a mess without a full-time preacher, and I'd never heard a sermon on grace before. As stupid as this sounds,
Trigun brought me back to the Lord. There, and people say that TV is just a distraction...