Narcissa Malfoy vs. the Nigerian Scammer, in which a Harry Potter fanwriter decides to respond to a scam email she received - in character as Narcissa Malfoy. She's got some other examples on her Livejournal as well.

What got me into scambaiting in the first place wasn't the writing side. It was the chance to photoshop fake documents and IDs for my characters to send to the scammers. I loved doing stuff that.

Unfortunately, I got into it just as the rules were changing, and people were starting to realise that we shouldn't send fake documents because the scammers could then use them and pretend to be our characters in other scams against real victims. :(