Originally Posted by Caligari

you could really have fun with that.

go over to his house like a jehovah's witness (or whatever religious freak variety you have in australia) and give him the sermon but mention things about the product you know he's selling and how you foresee him making a ton of money with it, or if you think he's a twat tell him surreptitiously how this thing is going to make his life a living hell on earth.

of course be vague about it, but give him just enough so he connects with the thing he's selling.

on edit- i am assuming he doesnt know that you know where he lives.