Geeklog Forums

Does anyone have any suggestions for forcing a temporary theme change for all users on a Geeklog site? I need to be able to change my site's default theme to a 'blacked out in tribute" theme easily and quickly on a fairly frequent basis. I could manually edit the site's 'config.php' file each time the change is required, but I'd rather have a plugin where I could activate the theme change and start a timer to automatically reset the theme back to normal after a set amount of time. Is this possible to do using a plugin or should I concentrate on writing a custom function to go in lib-custom.php?