Undefined terms overload

I was able to ignore it for a while, but now I have run into one in two unrelated threads. What does "bikeshedding" mean here? And, what does "OOB" mean here--the decodes with which I am familiar do not seem to fit: Out of Bounds, Out Of Body, Out of Bed, Out of Business, Open Of Business (used to see this one many times daily), Out Of Bullets, Out Of Band (also familiar from telephone days). -- The unique Characteristics of System Administrators: The fact that they are infallible; and, The fact that they learn from their mistakes. Quis custodiet ipsos custodes