Things got pretty ugly at a pre-St. Patrick's Day celebration at the University of Massachusetts' flagship Amherst campus. Its annual Blarney Blowout resulted in more than 70 arrests and four injured police officers. A crowd of about 4,000 partied at an off-campus housing complex Saturday. Police, equipped in riot gear, attempted to break it up with pepper spray after students threw rocks, glass bottles, and snowballs. After quieting that disturbance, several thousand people gathered again at a frat house, where more glass bottles were thrown at authorities. The police said charges include inciting to riot, failing to disperse, disorderly conduct, liquor law violations, and assault and battery on officers.