I wanted to record this nasty bug
If a Windows 2008 or 2008 R2 server has been 'up' for greater that 497 days, it will stop closing TCP ports that are in a TIME_WAIT status. Therefore, TCP/IP ports may be exhausted, and new TCP/IP sessions may not be created. This, of course would cause a number of application issues and even stop you RDPing to the server.
TCP/IP chimney offloading fails after 248.5 days. Therefore, systems will stop responding after 248.5 days if offloading connections are being used.
Of course this would also mean you are not patching frequently enough since you would have rebooted after most patches!!