The panel interview had just concluded, and the recruiter asked us: "Do you want to do the debrief now, or do you need a bio break?"
"Bio break," replied two people, who promptly got up from the table and left the room. Although I had never heard the phrase before, I deduced instantly what it meant.
For some people, it's not enough that we have replaced the word "toilet" with "bathroom." Apparently, "bathroom" is now a impolite word. Bio break allows the speaker to avoid either word.
Although a euphemism for using the toilet, its derivation (from "biological") means that the phrase extends to all manner of physiological needs and functions that might be required after a long period confined to a chair: eating, drinking, stretching legs, and smoking.
Although its use originated in the tech world, this bit of jargon is now used in business meetings in many industries and even appears on published conference schedules.
Addtional sources:
John Cowan, "Re: Why should I be embarassed when... " 20 May 1997. <alt.usage.english>
Michiko Kakutani, "When the Geeks Get Snide." New York Times. 27 June 2000. Reprinted at <http://www.cyberselfish.com/reviews5.html> (18 June 2004)