My favorite screensaver is "nose man" from xlockmore, but gnome screensaver seems no way to use it. I don't want to spend time to hack gnome-screensaver's configuration, instead, I found this alternative screen lock program - xautolock. Xautolock can lock the screen use any lock program, so it's possible to invoke xlockmore's binary "xlock" with whatever mode you like.
Xautolock also has a cool feature, it can lock the screen when the mouse is over a screen corner with a customized delay.
To install:
$ sudo apt-get install xlockmore xautolock
Here are the arguments to call xautolock, logged here to prevent read the long man page again.
# replace gnome-screensaver, lock screen if idle for 5 minutes, or
# mouse over a corner for 3 seconds
#
msg="All money go my home :-)"
/usr/bin/xautolock \
-corners ++++ -cornerdelay 3 -cornerredelay 30 \
-time 5 -locker "/usr/bin/xlock -mode nose -message '$msg'" &
Put this to
Since it's an X11 program, it could be started only after a user logged in
to X. To start it automatically for gnome X manager, use session manager
tool to add an entry is a handy way, "System" -> "Preference" ->
"Sessions"./etc/rc.local (for ubuntu), it will be
executed by /etc/rc2.d/S99rc.local on boot up.
Also, you can create a shortcut point to command xautolock
-locknow to lock the screen immediately.
Goodbye, gnome-screensaver.
$ killall gnome-screensaver $ sudo apt-get remove gnome-screensaver