Probably the easiest thing to do is just bring the subject up to anyone you happen to talk to. If I get into a conversation I try to bring up the ridiculous pot ban at some point.It takes time but eventually everybody gets comfortable with talking about it and they begin to see how many of there friends,neighbors and coworkers are indulging in the practice and they say "Hey these people don't seem like the crackheads I see on tv all the time.Maybe there is nothing wrong with smoking a little weed".
What we really need is an initiative at the federal level giving the US voters a chance to vote on this subject.