Originally posted by testuser
You could set a cron job to shutdown a machine, but I have no idea if it is possible to have one that will start it up again (after all the BSD system must be running to process the cron job).
A 3rd party app is not absolutely necessary. The crontab (chronological table?) file is right in your /etc directory. You can look at its contents from the Terminal with the command "cat /etc/crontab". Pick up a book on unix from your library, and you can learn how to modify it. But I don't think it can do the startups/shutdowns that you want it to.