Howard Marks is considered a hero/godto many a pot smoker in England, myself included. He is the reason that pot is sold in 'teenths, eighths, quarts, halves and ounces.
At the moment he travels the country doing a talk on his past, his jail sentance, the affects that pot can have on you and he also does a bit of DJing (mixing).
Also taught me how to skin up in person at a party about a year ago.