HTCondor is a high throughput computing system that can run multiple related tasks simultaneously. Most commonly, this means splitting up a job that runs over N events into M jobs that each run N/M events. However, that is just a simple example of what HTCondor can do.
In the case of MSU's tier3, condor is made up of several interacting systems.
To use HTCondor, a user minimally needs an executable and to create a condor submit scipt. The process for this can be found here, as well as information on more advanced topics.
-- ForrestPhillips - 14 Sep 2017