Think of it like an online Powerpoint where all the slides are live embeds of other websites. It's perfect for kiosk displays and superfluous lobby monitors, anywhere you've got a screen and a collection of sites you need to cycle through.
Site: sitecycler.com/
Blog Post: iamnotagoodartist.com/web/sitecycler/
Open source GPL. Attribution appreciated but not required. No warranty, no guarantee, use at your own risk, etc.