I put this in a sidebar block on my forums and tested it out. It's a great concept if it actually posted the event there reflecting the same day that the event is listed on the calendar.
http://www.norcalbots.com/forums have a look and see. In the calendar, I placed a new event titled GAME RELEASE | Call of Duty: Black Ops and set it as an all day event for November 9, 2010 but when it showed up in the block, it shows as the 8th. I probably wouldn't even have noticed the discrepancy if it hadn't been for the COD:Bops game.