420chan

420chan is an anonymous imageboard founded on 20 April 2005 by freelance web developer Aubrey Cottle. According to its founder, its name is a portmanteau of 420, a slang word originating in cannabis culture but now applicable to drug culture more generally, and 4chan, another imageboard website. Discussion on the site is primarily focused around recreational drug use and wrestling, with other boards related to topics including humor and academia.
While in its early history it was primarily known for hosting a board known as /i/, then used by the hacker collective Anonymous to stage "invasions" against individuals and web platforms such as Habbo Hotel, and Hal Turner. 
The modern incarnation of the website is primarily known for hosting discussions about psychoactive drugs legal and illegal. The site is also known for its LGBT discussion boards, /cd/ and /sd/.