The Bad Astronomer got a great piece of spam I haven't seen before, basically saying "Send me money or I WILL KILL YOU." With a great little story that the author is an assassin who's been paid to whack the recipient, but decided to give them one chance to outbid the client before he follows through. Awesome!
(I chuckle at the comments that are all OMG CALL POLICE, though. Yes, like your local PD can do anything about trolls in Latverian sub-basements hitting the 'send' button on their bulk mailer programs.)