As the host, you would be liable for everything illegal or harmful that happened to anyone. That includes violating state and local laws, failing to obtain required permits, providing alcohol to minors, failing to work with the utility companies to provide additional electricity and garbage service, failure to meet mandatory hygiene standards for restrooms, dealing with the inevitable illegal drug use, fights, sexual assaults, fires, drunk driving by those who attended the event, charges by the owner of the building, parking violations, etc., etc., etc. Some of these are minor violations and some are felonies with serious time in prison.
Answered on Mar 24th, 2014 at 2:34 PM