There are a few ways to describe what Condor is. Fundamentally Condor is based on the premise that computers are rarely used to their full potential. If my desktop computer is turned on while I'm at lunch or at home for the weekend then there is next to no work engaging the computer.
Condor allows people to share their machines when they are not using them in a controlled and secure way.
CondorIntroHowToSubmitJobs?CondorAdmins
-- EricMarshall - 07 Apr 2008