Credit card interest rate scam.  Voice msg said they'd been monitoring my credit cards for 6 mos, congratulations on my great payment history, and I've qualified for a zero interest rate on all mycards.  I guess they're going after two groups of people: those gullible enough to think they can get zero interest rates on all their cards, and anyone concerned that they might be monitoring their credit cards.  Both ideas preposterous, of course.  Caller name was sent as "Name Unavailabl" amusingly enough.