Conserving screen real-estate while still providing good content to the user has always been a challenge for designers and developers and while larger screen dimensions are becoming more prominent, it's still important to take full advantage of the space available to you. Jeeremie over at Web Kreation came up with a very cool method of display a login panel using MooTools v1.2's built-in effects capabilities:

Some of you were wondering what script I used to show/hide the login panel on top of this page (or in my latest Wordpress theme: ?Night Transition?). In this tutorial, we will see how to create a similar login/signup panel for your website using Mootools 1.2.

Jeeremie walks you through the steps of dropping this code into your site and provides the final source code as well to make the whole process painless. The end result is a very nice and intuitive slide down login panel which provides a nice balance of functionality and preserving screen real-estate.