Sophos is reporting that some malware has been seen in the wild that exploits the /Launch vulnerability in Adobe that has been a major discussion around security blogs lately. Adobe will not be releasing a patch for this until tomorrow (even though it was supposed to come out today), so this qualifies as a 'zero day'.
I'd probably recommend steering clear of opening any PDF files off the Internet until this is patched. At the very least, if you open a PDF and get a pop-up that says it is damaged, click "Do Not Open" no matter what the pop-up says to do.
Surf safe!