In preparation for Christmas and the premiere of this year's remaining Doctor Who specials, the BBC's official Doctor Who website launched their online advent calendar for 2009 on Tuesday. The advent calendar will feature many exclusive treats over the next twenty two days and door number three on the calendar is now available to open due to the fact that today is the third of December. Behind the door, there's a new video which takes an in depth look at Gadget from The Waters of Mars and you can view this video here. Content from behind the first two doors of the advent calendar can be found here and here in previous posts. This year's fourth door on the calendar will be available to open sometime tomorrow afternoon and details regarding the next special advent treat will be posted here on this site soon. What do you think of this new behind the scenes video?