You know those annoying scam emails you get from places like Nigeria or Ivory Coast, promising you millions of dollars if you can just help some poor slob of a bank manager or oil minister fake some documents?
There is a whole sport called scam-baiting. What some guys do is pretend to be interested, and string the scammers along--for weeks. Sometimes they even get trophies, typically ridiculous photographs or fake documents.
Two of my favorite sites for this are 419 Eater and The Scam Baiter.