sorry Devinder (I was viewing to see if anyone else had a good answer!).
I actually did a class a few years back after the method Principia Discordia refers to failed me, ending in a painful and embarrassing run-in - literally - with a metal garbage trolley. However, I don't know if the guy is still doing them, nor do I remember his name - he was doing it as a small business, so there's a chance it simply didn't take off for him. It was well worth the money and effort though.