Incidentally have you come across a spell which is proven - use the scientific method, if you know it - to actually work? I never have, and I know several dozen Harry Potter fans.
As for the poster talking about the girl who was 'writing spells in her bedroom' - sounds like the kid needs a lesson in reality, and maybe some attention from Mom and Dad. Don't blame Harry Potter for every bad thing that's happened in the last three years...
Listen to the interviews with the exorcist for the archdiocese of NY linked in #152