Leave it to me to leave out important things like which OS I'm using!
My machine is a dual 800 with Apple's 17" flat screen. (So I really can't turn off the monitor.) I'm on the latest OS X (10.2.6). My ocean waves are from a mp3 and I use Audion to play it. (iTunes STILL doesn't have an alarm, Audion does however.) I've never had any trouble with the screen waking like this except for the last several weeks.
This cron thing is an interesting idea. Perhaps something I installed recently is causing this. Is there a command for listing all cron processes?
Thanks for your suggestions so far!
Catrina