A man dressed in a green Santa suit holds a sign referring to Colorado legalizing marijuana at the 4/20 marijuana holiday in Civic Center Park in downtown Denver April 20, 2013. Thousands of marijuana enthusiasts gathered in Denver on Saturday for an annual weekend celebration of cannabis, the first such assemblage since Colorado voters legalized the recreational use of pot last fall. REUTERS/Rick Wilking (UNITED STATES - Tags: HEALTH SOCIETY POLITICS)