Mac screen saver?

[James Klock]

I'm looking for a screen saver for our public access internet workstations
(which happen to be Mac clones running System 7.6.3).  It should one way or
another put text on the screen, saying whatever short message I want it to.
 It should be either a control panel or a backgrounded application that
will NOT appear in the program list.  In a perfect world, it would also
allow applescripts to run in the background without disturbing either the
applescripts or the screen saver, but I can cope without that feature.

Any suggestions?

James