I've twitched local Waxwings on Christmas Day a couple of times, and occasionally had a look round the local patch (it's nice to get out of the house for a bit: family's all right but you know how it gets....
Many years ago (1988 was it?) news broke on Christmas Day on an American Robin at Inverbervie on the Scottish East coast and I know some people set off on Christmas Day. I'm willing to bet the locals nailed it on the day (and obviously one of them actually found it!) I didn't set off till Boxing Day, but still saw it, as well as a cracking Arctic Redpoll at Carnoustie golf course.