The November 2011 “Patch Tuesday” only features one critical patch. This patch affects Windows 7, Windows Vista,  and Windows 2008 Server R2, but does not affect Windows XP.

Microsoft is releasing three other bulletins, two are rated “important” and one is rated “moderate”. The remaining bulletins apply to Windows XP, Windows 7, Windows Vista, and Windows 2008 Server R2 and Windows 2003 Server.

It is unlikely that Microsoft will release a patch for the recently disclosed zero-day vulnerability exploited by the Duqu Trojan, widely dubbed "son of Stuxnet". The malware exploits a flaw in the Win32k TrueType font-parsing engine affected every version of Windows from XP to Windows 7. Microsoft has issued a temporary fix for the exploit, but said it will decide on whether to release a patch in the next monthly update or an out-of-band patch only once investigations are complete.

So leave your computers and servers on tonight and make sure to reboot them in the morning