I'm guessing it might be Spotlight. I have a spotlight process running as ' nobody' on my iMac. I also have a USB thing-a-ma-bob running as nobody:
<pre>/System/Library/PrivateFrameworks/MobileDevice.framework/Versio ns/A/Resources/usbmuxd -launchd</pre>
As for the scheduled maintenance scripts, they're run by launchd. Their plists are in /System/Library/LaunchDaemons, and can be read like so:
<pre>defaults read /System/Library/LaunchDaemons/com.apple.periodic-daily</pre>
<pre>defaults read /System/Library/LaunchDaemons/com.apple.periodic-weekly</pre>
<pre>defaults read /System/Library/LaunchDaemons/com.apple.periodic-monthly</pre>
The actual scripts themselves are in the daily, weekly, and monthly directories in /etc/periodic. The weekly one uses the find command, so it's possible it's that one. If your computer is asleep when the periodic script is supposed to run, it'll run later when it's awake, offset by however long your computer was asleep.
I would definitely undo the change you made to /etc/passwd, as you'd want that user to be enabled for other reasons. As for safety until you get your Airport Extreme, just make sure no services (like File sharing, etc., are turned on, and most importantly, have a good password on your accounts. All of them).
charlie