At the end of the second quarter, Kris Humphries hit KG hard in the face after KG shot the ball, clearly unnecessary contact. Rondo then went after Humphries and a brawl ensued. Rondo, Humphries, and Gerald Wallace were all ejected. KG received a technical but wasn't ejected. Rondo left the game with just 3 assists, not because he wasn't trying, but because no one could hit a shot.
The refs had a lot to do with the fight. They allowed excessive contact all night from the Nets and the Celtics were called for any contact. Consider the fact that at the half, the free throws were 17 for the Nets and 5 for the Celtics and three of the Celtics free throws were technical free throws. When a team is allowed to be that physical and the other team is called for every little foul, it causes a lot of frustration to build up. I expect Rondo to be suspended for at least one game and probably more. The refs should be fined as well, but I know it will never happen.