I got one a while back from a group of Soldiers in Iraq...
they were trying to give me 25,000,000 dollars... I sent them a very angry return email, because I investigated their unit and found it to be a group of wartime photographers. They picked the wrong kid to spam e-mail. I did it again with some nigerian thing and for the last 3 months I've been spam free...
perhaps you should tell them that "if they know your e-mail address they should find your home adress so you can kick their [expletive deleted] in person"
worked for me