Orlando Sentinel reports a man was seriously injured when a flying object struck him in the eye while riding Dragon Challenge in the Wizarding World of Harry Potter. No faults have been found with the roller coaster itself at this time, so we can only assume that this was just a freak accident, a la Fabio (who was hit in the head by a bird on a Busch Gardens coaster in 1999).
The man was reportedly in the front row of the coaster, which we speculate may put you at slightly greater risk of wayward objects. It seems that there was nothing either party could have done to prevent the terrible accident, but it does make you think twice about roller coaster safety.
8/17/11 - Following a second injury on Dragon Challenge, just a few weeks after the first, Universal announced that Dragon Challenge will no longer operate the two tracks simultaneously. Check out this post for more information.