There's an obvious morbid joke here about how this isn't the first time Dunn's had a car up his ass, but to be honest he was always one of my favorites from the Jackass crew -- so this is really sad news.
TMZ: Ryan Dunn Killed in Car Accident in Pennsylvania/6.20.11
Update: The Daily Beast has compiled some of Dunn's best moments. Damn, just -- damn. So long, dude.