Basically, a bunch of kids were participating in a particularly long lasting game of Risk on Coruscant. It was grueling. The game was about 3 weeks old, and the kids would take breaks and attend school, eat, and sleep. The armies were deadlocked, and finally, one kid made a breakthrough into Greenland from Iceland. This enraged his opponent, who had been carefully cultivating his defensive posture in North America. So he snapped, and flipped the board over, sending all the pieces sailing through the air and then all over the floor. The other kids freaked out, and a fight ensued. Somewhere in there, one of them called out "I hate you, you board-flipping mongoloid!" The quote was recorded by a passing security droid.
During the tussle, one of the kids knocked over a lamp. When the bulb burst, a spark set the curtains on fire. Within minutes, the house was ablaze. It spread quickly through the tightly packed residential areas of Coruscant, and soon a conflagration of epic proportions had engulfed entire sectors of the city-planet. The fire even knocked out power in part of the defense grid. Nervous residents stormed the Senate building, and demanded a swifter response to the catastrophe. They also thought it would be a good time to insist on a reboot to the Old Republic Calendar. This was the last straw, and the Senate finally responded by killing a lot of people, and ordering a few elite security staff to set fire to a few other planets in order to distract everyone. In the end, a bunch of people were dead, but it was really more of a general annoyance, or perhaps a disturbance, than a full blown crisis, battle, or war.