I love it when it snows in december. Look:
http://forum.hybrid-piloten.de/index.php
Aynone interested in porting
this mod (http://custom.simplemachines.org/mods/index.php?mod=2356) to ElkArte?
Here is a no frills version to get you started.
No frills since there are no options, install it and it will snow (outside of the admin area)
If you want moar flakes or different size or color then you will have to edit the NoFrillsSnow.integration.php file to do so. Note more flakes = moar CPU usage
If you want to turn off the snow, uninstall