4:20 or 4/20 (pronounced four-twenty) is a term used in North America to refer to the consumption of cannabis and, by extension, a way to identify oneself with the drug subculture around cannabis. 420 is common in cannabis culture. As April 20th is 4/20 it is the cannabis national holiday. Festivities abound about North America. One of the largest gathering is at the Boulder campus of Colorado University. In 2007 over 6,000 people were in high spirits.