The college professor walked into the classroom carrying two pizza boxes.
"Three hours from now, the Purge will begin. Once a year, our government allows murder to be legal for twelve hours.
"Some of you enjoy shooting people in the head, causing the brain matter to spill out. Others prefer slitting throats and watching the victim choke in their own blood. Cracking skulls with a baseball bat or burning people alive are popular too.
"I brought some pizza to celebrate, dig in," he told the class, knowing that the deadly poison in the food would take effect in three hours.