Hate the new calendar in Vista?  Not a fan of the Outlook calendar or don’t like the idea of always being connected to the web to use Google’s Calendar?  Love Open Source and all things Mozilla?  Then Sunbird is for you. Sunbird is a stand-alone calendar application.  If you want Sunbird to integrate with Thunderbird then you would want to install the Lightning extension.

Out of the box Sunbird has a very clean interface.  For you Firefox fans navigation will be pretty intuitive.

The Options and settings are very straight forward like with Firefox.

As with Firefox there are many extensions to add functionality to your calendar.  For a stand a lone calendar Sunbird is a lot more promising than Windows Calendar included in Vista.