Last year, Daylight Savings Time was moved around effective 2007. Quite a number of applications have been affected by this, including Windows, Exchange Server, SharePoint and CRM.  This was a change I didn't hear much about until a couple of days ago. There is a great Microsoft site on the Microsoft products affected and CRM is one of them. You can read the whole site here. There is a CRM specific Knowledge Base Article on the Hot Fix that will be available in March. You can read it here.