From RogerLSimon.com:
"Full Pajama Disclosure: I have noticed that some are casting aspersion on bloggers for working in their pajamas. I cannot tell a lie. I often do it. I also wrote screenplays for Warner Brothers, Universal and Twentieth Century Fox in my pajamas (do I have to give the money back?) and books for Simon & Schuster and Random House. I could go on... but I think you get the point. All together now:
'The pajama game
That's the game we're in
And we'll always be
In the pajama game
We love it!'"
ETYMOLOGICAL NOTE: According to the American Heritage online dictionary, the word "pajama" comes from the Hindi "pijma," for baggy pants, which in turn is based on the Middle Persian words "p" for leg plus "jmah" for garment.