Automatic screensaver for X

 XScreenSaver is a modular screen saver and locker for X11,
 containing more than 200 screen savers.
 .
 This package includes the bare minimum needed to blank and lock
 your screen. Install this package if you prefer xscreensaver to
 gnome-screensaver. If you prefer gnome-screensaver, you don't
 need to install this package.
 .
 The graphical display modes are in the xscreensaver-data,
 xscreensaver-data-extra, xscreensaver-gl and xscreensaver-gl-extra
 packages.