On a whim the other day I thought I'd build out an idea for navigation I had. It's nothing but a visual effect in which the hovered (or active) navigation item becomes the tallest "stair" and other items before and after it step down. It's simple, but it's not something you see very often. Probably for one major reason: you can't select "previous" elements in CSS.
http://css-tricks.com/stairway-navigation-a-jquery-plugin/
http://css-tricks.com/stairway-navigation-a-jquery-plugin/