Go the cell phone route one better and photograph the guy... or do all of society a favor and pull out a gun and just shoot him now. /rant mode off
I have no real answer for this sort of road clown... and I have had run-ins with those of similar ilk. It is really just effin' amazing that some folks chose to do this sort of thing and consider it "fun."
I too would love to hear a good answer to jerks of this nature.