This hint allows you to easily have a fully-interactive webpage as your desktop background.

Create a new web application using Fluid with the web site that you want as your desktop. Then launch that web application, and open its preferences. Go to the Appearances pane, and change the settings to the following:

• Window Style: Chromeless
• Window Level: Embed on Desktop
• Window Shadow: off

You may also want to adjust the opacity. I would suggest using DeskShdae to get rid of your desktop icons, setting your wallpaper to something the same color as your web app, and lowering the opacity as the page won't extend below the dock.

This hint isn't for everyone, but I like having my Google calendar with the Helvetical user script as my desktop.