If you have Google Desktop and want to add some Christmas decorations to your desktop, you can choose one of these gadgets.
A Christmas Tree that lights up more powerful if you use your computer's CPU more. Includes a small collection of Christmas songs (MIDI).
This tree looks better than the previous one and it's also customizable, but it doesn't have music or shiny lights.
Virtual Christmas Tree
You can actually decorate this tree (in the screenshot). While doing that, listen to carols and watch the snow fall.
All the trees can be detached from the sidebar and can be enlarged using the "Zoom" option.
Other holiday gadgets are available at Google Desktop site.