Adding a whole new twist to the conventional drop down menu idea, this script turns an ordinary UL list into a drill down style menu. The top level UL dictates the height of the menu, with the sub levels tucked away until navigated to. You can customize which level should be shown by default, whether to remember the last shown level when the page reloads, plus the speed of the "drilling" animation. Optional breadcrumb trails can be shown as well.