The act of rolling down a long steep hill in the hopes of performing various acrobatics in the air, but usually resulting in injuring oneself. It is the US equivalent of England's Gloucestershire cheese tossing.
Clyde: Did you here? Clarence and Joe are in the emergency room for spinal and neck injuries!
Rodney: What, did they go redneck tossing down that mountain near cousin eddy's again?
Rodney: Figures. Them two are good fer nuthin' hicks yehr me?