The Zip to Zap riot of May 9–11, 1969 in Zap, North Dakota, was originally intended as a spring break diversion. As a result of an article that originally appeared in the North Dakota State University's The Spectrum newspaper and was later picked up by the AP, between 2000 and 3000 people descended upon the small town of Zap, located in Mercer County in the west central part of the state, nearly 300 miles (482 km) from the NDSU campus. A few accounts have also referred to the name of the event as the "Zap-in".
Revelers drank copious quantities of alcohol. As the small country town's resources became depleted, the amiable mood began to turn ugly and Zap's residents asked the visitors to leave. Some complied, but others stayed behind. The event became a full-fledged riot. The National Guard was called in and the crowd was dispersed. The Zip to Zap would go down in history as the only official riot in the history of North Dakota that was put down by the National Guard.
This article is adapted from Wikipedia.