A website without URL!
This is for both Tiger and Leopard. It doesn't work in Camino and Firefox, it only works in Safari. Sometimes when you are browsing on the web and you click on a link, the website opens in a new window that doesn't have any URL bar. It sometimes might be nice to see the URL so that you can know whether you were redirected or you are still on the same website, or you might want to bookmark it. It looks like it is hidden, but hitting "Command - L" will bring it up instantly: