Glad you asked. Here's the true story about a boy who played with a ouija board.
If this is the big menace that you guys say it is, there should be more than one anecdote from 1949.
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...