Drupal’s menu system is really flexible and the menu blocks are versatile. Also there are a couple of 3rd party modules to display menus in all kinds of different ways.
Here is a quick PHP snippet to display a single level menu from Drupal…
The Drupal core and many modules use the jQuery package to create nice interactive effects. But it’s also a handy and easy to use tool for designers and authors!
Here is a quick example to show/hide a div with a nice slide effect, triggered from an adjoining element. If you know your CSS you can do all sort of tricks with this.