Is there an easy way to "lock" the screen under X (rather than sleeping the machine with the password option) so applications keep running in the background and keeping the "playful" at bay...

Turn the screensaver on (System Preferences->Desktop & Screen Saver). Choose an appropriate hot corner.

Under System Preferences->Security, check 'Require password to wake this computer from sleep or screen saver'

Then you can just mouse into the hot corner to start the screensaver and lock the machine. Really geeky people could use BlueTooth to sense when their mobile phone goes out of range and lock the screen then :)

Assuming you mean Mac OS X and not X-Windows of course :)

Have fun,
Shay
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=========================== Shay  Telfer ================================
 Perth, Western Australia   Technomancer  Join Team Sungroper in the
 Opinions for hire              [POQ]     2005 World Solar Challenge
 [EMAIL PROTECTED]         fnord     <http://sungroper.asn.au/>