There used to be a web site called "The Scam Baiter" where people posted their correspondence with various scammers. The funniest one was a guy convincing a scammer to pay the shipping for "Anus laptops", and IIRC he eventually managed to have a toilet shipped to Nigeria at the scammer's expense. The original thread is long gone, but I found an archived part of it:
http://postarchives.entensity.net/040105/scam.htm