Here is a fun site that is dedicated to the legalization of cannabis, with a focus on listing cannabis events from around the world. cannabis.wikia.com
The rallies and parades on the first weekend in may every year are based on and run in solidarity with the original legalization parade rally ever the New York City Cannabis Parade.
The current plan is to assemble at High Noon Saturday May 4 2013 on 24th st at Madison Ave, march down to Union Square via Broadway, to have a rally from 1pm until at least 5pm.
Redman is confirmed to open at Union Sq.