This may have dated back to a race in the spring in Martinsville when Jeff Gordon felt that Clint Bowyer cost him a win. 

Looks like Gordon felt it was payback time and after the bumping and rubbing, Gordon was black flagged and decided that he had taken just about enough. (WATCH THE VIDEO)

Crew members from Bowyer's pit ran to Gordon and grabbed him and started fighting. Gordon's crew members then got involved. Seconds later, Bowyer got out of his demolished #15 and took off toward the garage and Gordon's trailer. He was stopped before he could get in. They whole thing reminded me of the fight scene from Days Of Thunder. 

There is no doubt that fines and probably suspensions will come from this. Next week is the last race of the season.