Here comes christmas and you would have already activated the Christmas Wordpress Themes which would give your blog a beautiful christmas theme and you can run it till the New Year. Here is a Plugin which offers another Christmas effect on your blog named as the Christmas Snowfall Plugin, which shows some falling snow on your blog randomly towards the downwards direction.
You just need to download the plugin from here and activate it from your wordpress admin area and the plugin starts working with 10 snow flakes falling down. Hope this plugin helps you in making your blog looks more themed based this season.
Merry Christmas Everyone!