Computer jargon from the early days of computing is replete with a colorful — and often hilarious — vocabulary. “Juggling eggs” is one such phrase.
What does it mean?
Juggling eggs refers to keeping a lot of state in your head while modifying a program. “Don’t bother me now, I’m juggling eggs,” means that an interruption is likely to result in a scrambled program.
Source: The New Hacker’s Dictionary (Available as a book and online.)