We only went to stay for 24 hours but she managed to get out some classics before we left like:
'well it would have been lovely to spend xmas with the family' me 'well we did invite you' mum' yes well its not much fun going back to a hotel on christmas night'!! 
really, is that less fun than spending christmas day with your grandchildren and other family, having a meal cooked for you etc. Or you could sulk about being driven back to hotel 5 mins away for a peaceful nights sleep!
we also bought the gp's calendars made up of pics of the dc's. My IL's were thrilled with theirs and have shown it to everyone, my mother said 'well its nice but I would have preffered one of those digital photo frames that so and so got her mother'
and finally 'so you didnt buy me the cd i wanted then' (she previously asked for socks, which I bought, then 3 days before xmas declared she wanted a cd for mothers day, or xmas)
She has also said she couldnt afford to stay in hotel for 2 nights over xmas. This from a woman who spends £30 a week on wine and refuses to stay in cheaper budget hotel, would prefer posher one which is still only £55 inc full breakfast.
So glad me and dh are away when she comes to stay at end of month 