ZFriday is a small toy, developed as Zope Product and can be useful to bane MS Internet Explorer to stop it monopoly, exactly like friday_mod for Apache. :]
Once you've added an object instance (e.g. "zfriday"), you can simply add somewhere into standard_html_footer a tag:
<dtml-var zfriday>
And users, who uses MSIE all the time will see a Mozilla banner or page "Page unavailable today for MSIE Users" if "Friday" and "13" and will be asked to download Mozilla or Opera or Netscape. ;-) No offence intended, but I think it's rude to involve users in the browsers' war. I guess it's enough to let them know what advantages and disadvantages each browser has and not forcing them to choose one browser. After all, everybody is free of doing what he wants.
Greetings, Josef.