This one is wonderful, the perfect answer to the endless urban legend e-mails that circulate:
'I hate those hoax warnings, but this one is important!! Please send this to everyone on your e-mail list. If a man comes to your front door and says he is conducting a survey and asks you to show him your arse, do not show him your arse. This is a scam; he only wants to see your arse. I wish I'd got this yesterday. I feel so stupid and cheap.'
Courtesy of Felix at Leaving Munster.