Source : Free On-Line Dictionary of Computing

juggling eggs
     
        Keeping a lot of {state} in your head while modifying a
        program.  "Don't bother me now, I'm juggling eggs", means that
        an interrupt is likely to result in the program's being
        scrambled.  In the classic first-contact SF novel "The Mote in
        God's Eye", by Larry Niven and Jerry Pournelle, an alien
        describes a very difficult task by saying "We juggle priceless
        eggs in variable gravity."  See also {hack mode}.
     
        [{Jargon File}]