Thousands of supporters demanding that marijuana be legalized descended on Amherst over the weekend for an annual rally. The Amherst Common was the site of the 22d annual Extravaganja Saturday, hosted by the University of Massachusetts Amherst Cannabis Reform Coalition. The Daily Hampshire Gazette reported that one arrest was made. Organizers said an estimated 5,000 to 6,000 people attended the six-hour rally and music festival. Police Chief Scott Livingstone said traffic is usually more of a concern than crowd behavior. Possession of an ounce or less of marijuana is a civil violation in Massachusetts.