Self-Flagellation
Saint John Paul II did it to remind himself of Christ's sacrifice on the cross. Some Roman Catholics call it "taking the discipline" -- a small leather belt flung across the back while praying. That's about as far as most Christians will go. Some Shi'ite Muslims commemorate the martyrdom of Husayn ibn Ali with chains, blades, and other sharp objects in a procession that typically makes for a bloody scene. Saudi Arabia famously prohibits a lot of activity, but the country's Sunni leaders may have been onto something when they forbade any such public flagellation.
