Sounds like something very bad, doesn't it? Like what the police do to drunks in the cell. "Let's go cron job us a drunk."
The cron refers to time--chrono. Cron jobs are maintainence tasks that Unix systems perform at scheduled times. OS X has daily, weekly, and monthly jobs. If you leave your computer on 24/7, like Unix was meant to be, the jobs run at about 3am when they won't get in your way.