The Symantec folks identified a website exploiting a bug from this months Microsoft patches, specifically the Microsoft Internet Explorer Speech API 4 COM Object Instantiation Buffer Overflow Vulnerability.  Here is the URL to their blog entry:

http://www.symantec.com/enterprise/security_response/weblog/2007/06/deepsight_honeynet_detects_obf.html

Apparently, the actual exploit is similar to the proof of concept code posted on a popular exploit site ten days ago.