Target stores have been hacked, and 40 Million credit card accounts have been compromised. Even worse, it seems that Debit cards may have also been compromised, and that it's possible that PIN codes were recorded as well.
If you have used your Debit card at a Target store since Thanksgiving, you need to change your PIN immediately. While the credit card companies will cover losses on compromised credit cards, if the Bad Guys can clone your Debit card and use your PIN then they can clean out your bank account. The bank may or may not cover this.
Mrs Borepatch and I are in the process of changing our PINs. I strongly recommend you do the same, immediately.
Information is still sketchy on the details, but this is potentially so bad that I'm putting up an alert. In five and a half years of blogging on security issues I've never done this before. That's how serious this is.
UPDATE 19 December 2013 11:11: Reports are that this has been going on since Black Thursday. My guess (and that's all it is) is that this could have been going on much longer. If you've been using a Debit card at Target for the last 6 months or so, change your PIN.