I love Christmas and I love mobile phones, so imagine my delight when I came across the X'mas Theme Pack. The download allows you to apply some seasonal magic to your phone, automatically altering its home screen with a winter wonderland theme.
The pack decks the home screen with misteltoe, snow and Christmas greetings. It also replaces the default Start menu and alters the colour and appearance of some of the menus and toolbars on the Windows Mobile OS.
Personally I don't think this theme has gone far enough. The changes it makes are quite subtle and there's no imagery of Santa or presents or anything.