Everybody is mentioning the "easy way out." Here's a sample
for you. Suppose the next page that you want to display is
www.mysite.com/testover.html. You want to
switch to that page in 20 minutes (1200 seconds). You would
simply include the following tag in the
<head>
section of your page (whether delivered from a Perl script or
from a static document):
<META HTTP-EQUIV="refresh" Content="1200; http://www.mysite.com/testov
+er.html">
Update: Hack noted by
Cubes below is very
true. Anything delivered in HTML to a browser can be saved
and gone back to. An
embedded app is probably
the only way to do what you want without fear of compromise.